Exemplo n.º 1
0
static int help(struct sk_buff *skb, unsigned int protoff,
		struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
	unsigned int dataoff;
	const struct iphdr *iph;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	char *data, *data_limit, *ib_ptr;
	int dir = CTINFO2DIR(ctinfo);
	struct nf_conntrack_expect *exp;
	struct nf_conntrack_tuple *tuple;
	u_int32_t dcc_ip;
	u_int16_t dcc_port;
	__be16 port;
	int i, ret = NF_ACCEPT;
	char *addr_beg_p, *addr_end_p;
	typeof(nf_nat_irc_hook) nf_nat_irc;

	/* If packet is coming from IRC server */
	if (dir == IP_CT_DIR_REPLY)
		return NF_ACCEPT;

	/* Until there's been traffic both ways, don't look in packets. */
	if (ctinfo != IP_CT_ESTABLISHED &&
	    ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY)
		return NF_ACCEPT;

	/* Not a full tcp header? */
	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
	if (th == NULL)
		return NF_ACCEPT;

	/* No data? */
	dataoff = protoff + th->doff*4;
	if (dataoff >= skb->len)
		return NF_ACCEPT;

	spin_lock_bh(&irc_buffer_lock);
	ib_ptr = skb_header_pointer(skb, dataoff, skb->len - dataoff,
				    irc_buffer);
	BUG_ON(ib_ptr == NULL);

	data = ib_ptr;
	data_limit = ib_ptr + skb->len - dataoff;

	/* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24
	 * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */
	while (data < data_limit - (19 + MINMATCHLEN)) {
		if (memcmp(data, "\1DCC ", 5)) {
			data++;
			continue;
		}
		data += 5;
		/* we have at least (19+MINMATCHLEN)-5 bytes valid data left */

		iph = ip_hdr(skb);
		pr_debug("DCC found in master %pI4:%u %pI4:%u\n",
			 &iph->saddr, ntohs(th->source),
			 &iph->daddr, ntohs(th->dest));

		for (i = 0; i < ARRAY_SIZE(dccprotos); i++) {
			if (memcmp(data, dccprotos[i], strlen(dccprotos[i]))) {
				/* no match */
				continue;
			}
			data += strlen(dccprotos[i]);
			pr_debug("DCC %s detected\n", dccprotos[i]);

			/* we have at least
			 * (19+MINMATCHLEN)-5-dccprotos[i].matchlen bytes valid
			 * data left (== 14/13 bytes) */
			if (parse_dcc((char *)data, data_limit, &dcc_ip,
				       &dcc_port, &addr_beg_p, &addr_end_p)) {
				pr_debug("unable to parse dcc command\n");
				continue;
			}
			pr_debug("DCC bound ip/port: %pI4:%u\n",
				&dcc_ip, dcc_port);

			/* dcc_ip can be the internal OR external (NAT'ed) IP */
			tuple = &ct->tuplehash[dir].tuple;
			if (tuple->src.u3.ip != htonl(dcc_ip) &&
			    tuple->dst.u3.ip != htonl(dcc_ip)) {
				if (net_ratelimit())
					printk(KERN_WARNING
						"Forged DCC command from %pI4: %pI4:%u\n",
						&tuple->src.u3.ip,
						&dcc_ip, dcc_port);
				continue;
			}

			exp = nf_conntrack_expect_alloc(ct);
			if (exp == NULL) {
				ret = NF_DROP;
				goto out;
			}
			tuple = &ct->tuplehash[!dir].tuple;
			port = htons(dcc_port);
			nf_conntrack_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
						 tuple->src.l3num,
						 NULL, &tuple->dst.u3,
						 IPPROTO_TCP, NULL, &port);

			nf_nat_irc = rcu_dereference(nf_nat_irc_hook);
			if (nf_nat_irc && ct->status & IPS_NAT_MASK)
				ret = nf_nat_irc(skb, ctinfo,
						 addr_beg_p - ib_ptr,
						 addr_end_p - addr_beg_p,
						 exp);
			else if (nf_conntrack_expect_related(exp) != 0)
				ret = NF_DROP;
			nf_conntrack_expect_put(exp);
			goto out;
		}
	}
 out:
	spin_unlock_bh(&irc_buffer_lock);
	return ret;
}
Exemplo n.º 2
0
struct sock*
xt_socket_get4_sk(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct iphdr *iph = ip_hdr(skb);
	struct udphdr _hdr, *hp = NULL;
	struct sock *sk;
	__be32 daddr, saddr;
	__be16 dport, sport;
	u8 protocol;
#ifdef XT_SOCKET_HAVE_CONNTRACK
	struct nf_conn const *ct;
	enum ip_conntrack_info ctinfo;
#endif

	daddr = saddr = dport = sport = protocol = 0;

	if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) {
		hp = skb_header_pointer(skb, ip_hdrlen(skb),
					sizeof(_hdr), &_hdr);
		if (hp == NULL)
			return NULL;

		protocol = iph->protocol;
		saddr = iph->saddr;
		sport = hp->source;
		daddr = iph->daddr;
		dport = hp->dest;

	} else if (iph->protocol == IPPROTO_ICMP) {
		if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr,
					&sport, &dport))
			return NULL;
	} else {
		return NULL;
	}

#ifdef XT_SOCKET_HAVE_CONNTRACK
	/* Do the lookup with the original socket address in case this is a
	 * reply packet of an established SNAT-ted connection. */

	ct = nf_ct_get(skb, &ctinfo);
	if (ct && !nf_ct_is_untracked(ct) &&
	    ((iph->protocol != IPPROTO_ICMP &&
	      ctinfo == IP_CT_ESTABLISHED_REPLY) ||
	     (iph->protocol == IPPROTO_ICMP &&
	      ctinfo == IP_CT_RELATED_REPLY)) &&
	    (ct->status & IPS_SRC_NAT_DONE)) {

		daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
		dport = (iph->protocol == IPPROTO_TCP) ?
			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port :
			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
	}
#endif

	sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), protocol,
				   saddr, daddr, sport, dport, par->in, NFT_LOOKUP_ANY);

	pr_debug("proto %hhu %pI4:%hu -> %pI4:%hu (orig %pI4:%hu) sock %p\n",
		 protocol, &saddr, ntohs(sport),
		 &daddr, ntohs(dport),
		 &iph->daddr, hp ? ntohs(hp->dest) : 0, sk);

	return sk;
}
Exemplo n.º 3
0
/* track caller id inside control connection, call expect_related */
static int
conntrack_pptp_help(struct sk_buff *skb, unsigned int protoff,
		    struct nf_conn *ct, enum ip_conntrack_info ctinfo)

{
	int dir = CTINFO2DIR(ctinfo);
	const struct nf_ct_pptp_master *info = &nfct_help(ct)->help.ct_pptp_info;
	const struct tcphdr *tcph;
	struct tcphdr _tcph;
	const struct pptp_pkt_hdr *pptph;
	struct pptp_pkt_hdr _pptph;
	struct PptpControlHeader _ctlh, *ctlh;
	union pptp_ctrl_union _pptpReq, *pptpReq;
	unsigned int tcplen = skb->len - protoff;
	unsigned int datalen, reqlen, nexthdr_off;
	int oldsstate, oldcstate;
	int ret;
	u_int16_t msg;

#ifdef CONFIG_HTC_NET_MODIFY
    if (info == NULL)
        printk("[NET] info = NULL in %s\n", __func__);
#endif

	/* don't do any tracking before tcp handshake complete */
	if (ctinfo != IP_CT_ESTABLISHED &&
	    ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY)
		return NF_ACCEPT;

	nexthdr_off = protoff;
	tcph = skb_header_pointer(skb, nexthdr_off, sizeof(_tcph), &_tcph);
	BUG_ON(!tcph);
	nexthdr_off += tcph->doff * 4;
	datalen = tcplen - tcph->doff * 4;

	pptph = skb_header_pointer(skb, nexthdr_off, sizeof(_pptph), &_pptph);
	if (!pptph) {
		pr_debug("no full PPTP header, can't track\n");
		return NF_ACCEPT;
	}
	nexthdr_off += sizeof(_pptph);
	datalen -= sizeof(_pptph);

	/* if it's not a control message we can't do anything with it */
	if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL ||
	    ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE) {
		pr_debug("not a control packet\n");
		return NF_ACCEPT;
	}

	ctlh = skb_header_pointer(skb, nexthdr_off, sizeof(_ctlh), &_ctlh);
	if (!ctlh)
		return NF_ACCEPT;
	nexthdr_off += sizeof(_ctlh);
	datalen -= sizeof(_ctlh);

	reqlen = datalen;
	msg = ntohs(ctlh->messageType);
	if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg])
		return NF_ACCEPT;
	if (reqlen > sizeof(*pptpReq))
		reqlen = sizeof(*pptpReq);

	pptpReq = skb_header_pointer(skb, nexthdr_off, reqlen, &_pptpReq);
	if (!pptpReq)
		return NF_ACCEPT;

	oldsstate = info->sstate;
	oldcstate = info->cstate;

	spin_lock_bh(&nf_pptp_lock);

	/* FIXME: We just blindly assume that the control connection is always
	 * established from PNS->PAC.  However, RFC makes no guarantee */
	if (dir == IP_CT_DIR_ORIGINAL)
		/* client -> server (PNS -> PAC) */
		ret = pptp_outbound_pkt(skb, ctlh, pptpReq, reqlen, ct,
					ctinfo);
	else
		/* server -> client (PAC -> PNS) */
		ret = pptp_inbound_pkt(skb, ctlh, pptpReq, reqlen, ct,
				       ctinfo);
	pr_debug("sstate: %d->%d, cstate: %d->%d\n",
		 oldsstate, info->sstate, oldcstate, info->cstate);
	spin_unlock_bh(&nf_pptp_lock);

	return ret;
}
/* Returns verdict for packet, or -1 for invalid. */
static int tcp_packet(struct nf_conn *conntrack,
		      const struct sk_buff *skb,
		      unsigned int dataoff,
		      enum ip_conntrack_info ctinfo,
		      int pf,
		      unsigned int hooknum)
{
	enum tcp_conntrack new_state, old_state;
	enum ip_conntrack_dir dir;
	struct tcphdr *th, _tcph;
	unsigned long timeout;
	unsigned int index;

	th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
	BUG_ON(th == NULL);

	write_lock_bh(&tcp_lock);
	old_state = conntrack->proto.tcp.state;
	dir = CTINFO2DIR(ctinfo);
	index = get_conntrack_index(th);
	new_state = tcp_conntracks[dir][index][old_state];

	switch (new_state) {
	case TCP_CONNTRACK_IGNORE:
		/* Ignored packets:
		 *
		 * a) SYN in ORIGINAL
		 * b) SYN/ACK in REPLY
		 * c) ACK in reply direction after initial SYN in original.
		 */
		if (index == TCP_SYNACK_SET
		    && conntrack->proto.tcp.last_index == TCP_SYN_SET
		    && conntrack->proto.tcp.last_dir != dir
		    && ntohl(th->ack_seq) ==
			     conntrack->proto.tcp.last_end) {
			/* This SYN/ACK acknowledges a SYN that we earlier
			 * ignored as invalid. This means that the client and
			 * the server are both in sync, while the firewall is
			 * not. We kill this session and block the SYN/ACK so
			 * that the client cannot but retransmit its SYN and
			 * thus initiate a clean new session.
			 */
			write_unlock_bh(&tcp_lock);
			if (LOG_INVALID(IPPROTO_TCP))
				nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
					  "nf_ct_tcp: killing out of sync session ");
			if (del_timer(&conntrack->timeout))
				conntrack->timeout.function((unsigned long)
							    conntrack);
			return -NF_DROP;
		}
		conntrack->proto.tcp.last_index = index;
		conntrack->proto.tcp.last_dir = dir;
		conntrack->proto.tcp.last_seq = ntohl(th->seq);
		conntrack->proto.tcp.last_end =
		    segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);

		write_unlock_bh(&tcp_lock);
		if (LOG_INVALID(IPPROTO_TCP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				  "nf_ct_tcp: invalid packed ignored ");
		return NF_ACCEPT;
	case TCP_CONNTRACK_MAX:
		/* Invalid packet */
		DEBUGP("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
		       dir, get_conntrack_index(th),
		       old_state);
		write_unlock_bh(&tcp_lock);
		if (LOG_INVALID(IPPROTO_TCP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				  "nf_ct_tcp: invalid state ");
		return -NF_ACCEPT;
	case TCP_CONNTRACK_SYN_SENT:
		if (old_state < TCP_CONNTRACK_TIME_WAIT)
			break;
		if ((conntrack->proto.tcp.seen[dir].flags &
			IP_CT_TCP_FLAG_CLOSE_INIT)
		    || after(ntohl(th->seq),
			     conntrack->proto.tcp.seen[dir].td_end)) {
			/* Attempt to reopen a closed connection.
			* Delete this connection and look up again. */
			write_unlock_bh(&tcp_lock);
			if (del_timer(&conntrack->timeout))
				conntrack->timeout.function((unsigned long)
							    conntrack);
			return -NF_REPEAT;
		} else {
			write_unlock_bh(&tcp_lock);
			if (LOG_INVALID(IPPROTO_TCP))
				nf_log_packet(pf, 0, skb, NULL, NULL,
					      NULL, "nf_ct_tcp: invalid SYN");
			return -NF_ACCEPT;
		}
	case TCP_CONNTRACK_CLOSE:
		if (index == TCP_RST_SET
		    && ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)
			 && conntrack->proto.tcp.last_index == TCP_SYN_SET)
			|| (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
			    && conntrack->proto.tcp.last_index == TCP_ACK_SET))
		    && ntohl(th->ack_seq) == conntrack->proto.tcp.last_end) {
			/* RST sent to invalid SYN or ACK we had let through
			 * at a) and c) above:
			 *
			 * a) SYN was in window then
			 * c) we hold a half-open connection.
			 *
			 * Delete our connection entry.
			 * We skip window checking, because packet might ACK
			 * segments we ignored. */
			goto in_window;
		}
		/* Just fall through */
	default:
		/* Keep compilers happy. */
		break;
	}

	if (!tcp_in_window(&conntrack->proto.tcp, dir, index,
			   skb, dataoff, th, pf)) {
		write_unlock_bh(&tcp_lock);
		return -NF_ACCEPT;
	}
     in_window:
	/* From now on we have got in-window packets */
	conntrack->proto.tcp.last_index = index;

	DEBUGP("tcp_conntracks: src=%u.%u.%u.%u:%hu dst=%u.%u.%u.%u:%hu "
	       "syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
		NIPQUAD(iph->saddr), ntohs(th->source),
		NIPQUAD(iph->daddr), ntohs(th->dest),
		(th->syn ? 1 : 0), (th->ack ? 1 : 0),
		(th->fin ? 1 : 0), (th->rst ? 1 : 0),
		old_state, new_state);

	conntrack->proto.tcp.state = new_state;
	if (old_state != new_state
	    && (new_state == TCP_CONNTRACK_FIN_WAIT
		|| new_state == TCP_CONNTRACK_CLOSE))
		conntrack->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
	timeout = conntrack->proto.tcp.retrans >= nf_ct_tcp_max_retrans
		  && *tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
		  ? nf_ct_tcp_timeout_max_retrans : *tcp_timeouts[new_state];
	write_unlock_bh(&tcp_lock);

	nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
	if (new_state != old_state)
		nf_conntrack_event_cache(IPCT_PROTOINFO, skb);

	if (!test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
		/* If only reply is a RST, we can consider ourselves not to
		   have an established connection: this is a fairly common
		   problem case, so we can delete the conntrack
		   immediately.  --RR */
		if (th->rst) {
			if (del_timer(&conntrack->timeout))
				conntrack->timeout.function((unsigned long)
							    conntrack);
			return NF_ACCEPT;
		}
	} else if (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
		   && (old_state == TCP_CONNTRACK_SYN_RECV
		       || old_state == TCP_CONNTRACK_ESTABLISHED)
		   && new_state == TCP_CONNTRACK_ESTABLISHED) {
		/* Set ASSURED if we see see valid ack in ESTABLISHED
		   after SYN_RECV or a valid answer for a picked up
		   connection. */
		set_bit(IPS_ASSURED_BIT, &conntrack->status);
		nf_conntrack_event_cache(IPCT_STATUS, skb);
	}
	nf_ct_refresh_acct(conntrack, ctinfo, skb, timeout);

	return NF_ACCEPT;
}
static unsigned int ipv6_synproxy_hook(unsigned int hooknum,
				       struct sk_buff *skb,
				       const struct net_device *in,
				       const struct net_device *out,
				       int (*okfn)(struct sk_buff *))
{
	struct synproxy_net *snet = synproxy_pernet(dev_net(in ? : out));
	enum ip_conntrack_info ctinfo;
	struct nf_conn *ct;
	struct nf_conn_synproxy *synproxy;
	struct synproxy_options opts = {};
	const struct ip_ct_tcp *state;
	struct tcphdr *th, _th;
	__be16 frag_off;
	u8 nexthdr;
	int thoff;

	ct = nf_ct_get(skb, &ctinfo);
	if (ct == NULL)
		return NF_ACCEPT;

	synproxy = nfct_synproxy(ct);
	if (synproxy == NULL)
		return NF_ACCEPT;

	if (nf_is_loopback_packet(skb))
		return NF_ACCEPT;

	nexthdr = ipv6_hdr(skb)->nexthdr;
	thoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
				 &frag_off);
	if (thoff < 0)
		return NF_ACCEPT;

	th = skb_header_pointer(skb, thoff, sizeof(_th), &_th);
	if (th == NULL)
		return NF_DROP;

	state = &ct->proto.tcp;
	switch (state->state) {
	case TCP_CONNTRACK_CLOSE:
		if (th->rst && !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
			nf_ct_seqadj_init(ct, ctinfo, synproxy->isn -
						      ntohl(th->seq) + 1);
			break;
		}

		if (!th->syn || th->ack ||
		    CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
			break;

		/* Reopened connection - reset the sequence number and timestamp
		 * adjustments, they will get initialized once the connection is
		 * reestablished.
		 */
		nf_ct_seqadj_init(ct, ctinfo, 0);
		synproxy->tsoff = 0;
		this_cpu_inc(snet->stats->conn_reopened);

		/* fall through */
	case TCP_CONNTRACK_SYN_SENT:
		if (!synproxy_parse_options(skb, thoff, th, &opts))
			return NF_DROP;

		if (!th->syn && th->ack &&
		    CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
			/* Keep-Alives are sent with SEG.SEQ = SND.NXT-1,
			 * therefore we need to add 1 to make the SYN sequence
			 * number match the one of first SYN.
			 */
			if (synproxy_recv_client_ack(snet, skb, th, &opts,
						     ntohl(th->seq) + 1))
				this_cpu_inc(snet->stats->cookie_retrans);

			return NF_DROP;
		}

		synproxy->isn = ntohl(th->ack_seq);
		if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP)
			synproxy->its = opts.tsecr;
		break;
	case TCP_CONNTRACK_SYN_RECV:
		if (!th->syn || !th->ack)
			break;

		if (!synproxy_parse_options(skb, thoff, th, &opts))
			return NF_DROP;

		if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP)
			synproxy->tsoff = opts.tsval - synproxy->its;

		opts.options &= ~(XT_SYNPROXY_OPT_MSS |
				  XT_SYNPROXY_OPT_WSCALE |
				  XT_SYNPROXY_OPT_SACK_PERM);

		swap(opts.tsval, opts.tsecr);
		synproxy_send_server_ack(snet, state, skb, th, &opts);

		nf_ct_seqadj_init(ct, ctinfo, synproxy->isn - ntohl(th->seq));

		swap(opts.tsval, opts.tsecr);
		synproxy_send_client_ack(snet, skb, th, &opts);

		consume_skb(skb);
		return NF_STOLEN;
	default:
		break;
	}

	synproxy_tstamp_adjust(skb, thoff, th, ct, ctinfo, synproxy);
	return NF_ACCEPT;
}
Exemplo n.º 6
0
static int dump_tcp_header(struct sbuff *m, const struct sk_buff *skb,
			   u8 proto, int fragment, unsigned int offset,
			   unsigned int logflags)
{
	struct tcphdr _tcph;
	const struct tcphdr *th;

	/* Max length: 10 "PROTO=TCP " */
	sb_add(m, "PROTO=TCP ");

	if (fragment)
		return 0;

	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
	th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
	if (th == NULL) {
		sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
		return 1;
	}

	/* Max length: 20 "SPT=65535 DPT=65535 " */
	sb_add(m, "SPT=%u DPT=%u ", ntohs(th->source), ntohs(th->dest));
	/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
	if (logflags & XT_LOG_TCPSEQ)
		sb_add(m, "SEQ=%u ACK=%u ", ntohl(th->seq), ntohl(th->ack_seq));

	/* Max length: 13 "WINDOW=65535 " */
	sb_add(m, "WINDOW=%u ", ntohs(th->window));
	/* Max length: 9 "RES=0x3C " */
	sb_add(m, "RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) &
					    TCP_RESERVED_BITS) >> 22));
	/* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
	if (th->cwr)
		sb_add(m, "CWR ");
	if (th->ece)
		sb_add(m, "ECE ");
	if (th->urg)
		sb_add(m, "URG ");
	if (th->ack)
		sb_add(m, "ACK ");
	if (th->psh)
		sb_add(m, "PSH ");
	if (th->rst)
		sb_add(m, "RST ");
	if (th->syn)
		sb_add(m, "SYN ");
	if (th->fin)
		sb_add(m, "FIN ");
	/* Max length: 11 "URGP=65535 " */
	sb_add(m, "URGP=%u ", ntohs(th->urg_ptr));

	if ((logflags & XT_LOG_TCPOPT) && th->doff*4 > sizeof(struct tcphdr)) {
		u_int8_t _opt[60 - sizeof(struct tcphdr)];
		const u_int8_t *op;
		unsigned int i;
		unsigned int optsize = th->doff*4 - sizeof(struct tcphdr);

		op = skb_header_pointer(skb, offset + sizeof(struct tcphdr),
					optsize, _opt);
		if (op == NULL) {
			sb_add(m, "OPT (TRUNCATED)");
			return 1;
		}

		/* Max length: 127 "OPT (" 15*4*2chars ") " */
		sb_add(m, "OPT (");
		for (i = 0; i < optsize; i++)
			sb_add(m, "%02X", op[i]);

		sb_add(m, ") ");
	}

	return 0;
}
/* Called when a new connection for this protocol found. */
static int tcp_new(struct nf_conn *conntrack,
		   const struct sk_buff *skb,
		   unsigned int dataoff)
{
	enum tcp_conntrack new_state;
	struct tcphdr *th, _tcph;
#ifdef DEBUGP_VARS
	struct ip_ct_tcp_state *sender = &conntrack->proto.tcp.seen[0];
	struct ip_ct_tcp_state *receiver = &conntrack->proto.tcp.seen[1];
#endif

	th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
	BUG_ON(th == NULL);

	/* Don't need lock here: this conntrack not in circulation yet */
	new_state
		= tcp_conntracks[0][get_conntrack_index(th)]
		[TCP_CONNTRACK_NONE];

	/* Invalid: delete conntrack */
	if (new_state >= TCP_CONNTRACK_MAX) {
		DEBUGP("nf_ct_tcp: invalid new deleting.\n");
		return 0;
	}

	if (new_state == TCP_CONNTRACK_SYN_SENT) {
		/* SYN packet */
		conntrack->proto.tcp.seen[0].td_end =
			segment_seq_plus_len(ntohl(th->seq), skb->len,
					     dataoff, th);
		conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
		if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
			conntrack->proto.tcp.seen[0].td_maxwin = 1;
		conntrack->proto.tcp.seen[0].td_maxend =
			conntrack->proto.tcp.seen[0].td_end;

		tcp_options(skb, dataoff, th, &conntrack->proto.tcp.seen[0]);
		conntrack->proto.tcp.seen[1].flags = 0;
	} else if (nf_ct_tcp_loose == 0) {
		/* Don't try to pick up connections. */
		return 0;
	} else {
		/*
		 * We are in the middle of a connection,
		 * its history is lost for us.
		 * Let's try to use the data from the packet.
		 */
		conntrack->proto.tcp.seen[0].td_end =
			segment_seq_plus_len(ntohl(th->seq), skb->len,
					     dataoff, th);
		conntrack->proto.tcp.seen[0].td_maxwin = ntohs(th->window);
		if (conntrack->proto.tcp.seen[0].td_maxwin == 0)
			conntrack->proto.tcp.seen[0].td_maxwin = 1;
		conntrack->proto.tcp.seen[0].td_maxend =
			conntrack->proto.tcp.seen[0].td_end +
			conntrack->proto.tcp.seen[0].td_maxwin;
		conntrack->proto.tcp.seen[0].td_scale = 0;

		/* We assume SACK and liberal window checking to handle
		 * window scaling */
		conntrack->proto.tcp.seen[0].flags =
		conntrack->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM |
						     IP_CT_TCP_FLAG_BE_LIBERAL;
	}

	conntrack->proto.tcp.seen[1].td_end = 0;
	conntrack->proto.tcp.seen[1].td_maxend = 0;
	conntrack->proto.tcp.seen[1].td_maxwin = 1;
	conntrack->proto.tcp.seen[1].td_scale = 0;

	/* tcp_packet will set them */
	conntrack->proto.tcp.state = TCP_CONNTRACK_NONE;
	conntrack->proto.tcp.last_index = TCP_NONE_SET;

	DEBUGP("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
	       "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
		sender->td_end, sender->td_maxend, sender->td_maxwin,
		sender->td_scale,
		receiver->td_end, receiver->td_maxend, receiver->td_maxwin,
		receiver->td_scale);
	return 1;
}
int
ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
		  struct ip_vs_protocol *pp)
{
	struct rt6_info *rt;		/* Route to the other host */
	int mtu;
	int local;

	EnterFunction(10);

	/* check if it is a connection of no-client-port */
	if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
		__be16 _pt, *p;
		p = skb_header_pointer(skb, sizeof(struct ipv6hdr),
				       sizeof(_pt), &_pt);
		if (p == NULL)
			goto tx_error;
		ip_vs_conn_fill_cport(cp, *p);
		IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
	}

	if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6, NULL,
					 0, (IP_VS_RT_MODE_LOCAL |
					     IP_VS_RT_MODE_NON_LOCAL |
					     IP_VS_RT_MODE_RDR))))
		goto tx_error_icmp;
	local = __ip_vs_is_local_route6(rt);
	/*
	 * Avoid duplicate tuple in reply direction for NAT traffic
	 * to local address when connection is sync-ed
	 */
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
	if (cp->flags & IP_VS_CONN_F_SYNC && local) {
		enum ip_conntrack_info ctinfo;
		struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);

		if (ct && !nf_ct_is_untracked(ct)) {
			IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, 0,
					 "ip_vs_nat_xmit_v6(): "
					 "stopping DNAT to local address");
			goto tx_error_put;
		}
	}
#endif

	/* From world but DNAT to loopback address? */
	if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
	    ipv6_addr_type(&rt->rt6i_dst.addr) & IPV6_ADDR_LOOPBACK) {
		IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, 0,
				 "ip_vs_nat_xmit_v6(): "
				 "stopping DNAT to loopback address");
		goto tx_error_put;
	}

	/* MTU checking */
	mtu = dst_mtu(&rt->dst);
	if (skb->len > mtu && !skb_is_gso(skb)) {
		if (!skb->dev) {
			struct net *net = dev_net(skb_dst(skb)->dev);

			skb->dev = net->loopback_dev;
		}
		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
		IP_VS_DBG_RL_PKT(0, AF_INET6, pp, skb, 0,
				 "ip_vs_nat_xmit_v6(): frag needed for");
		goto tx_error_put;
	}

	/* copy-on-write the packet before mangling it */
	if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
		goto tx_error_put;

	if (skb_cow(skb, rt->dst.dev->hard_header_len))
		goto tx_error_put;

	/* mangle the packet */
	if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp))
		goto tx_error;
	ipv6_hdr(skb)->daddr = cp->daddr.in6;

	if (!local || !skb->dev) {
		/* drop the old route when skb is not shared */
		skb_dst_drop(skb);
		skb_dst_set(skb, &rt->dst);
	} else {
		/* destined to loopback, do we need to change route? */
		dst_release(&rt->dst);
	}

	IP_VS_DBG_PKT(10, AF_INET6, pp, skb, 0, "After DNAT");

	/* FIXME: when application helper enlarges the packet and the length
	   is larger than the MTU of outgoing device, there will be still
	   MTU problem. */

	/* Another hack: avoid icmp_send in ip_fragment */
	skb->local_df = 1;

	IP_VS_XMIT_NAT(NFPROTO_IPV6, skb, cp, local);

	LeaveFunction(10);
	return NF_STOLEN;

tx_error_icmp:
	dst_link_failure(skb);
tx_error:
	LeaveFunction(10);
	kfree_skb(skb);
	return NF_STOLEN;
tx_error_put:
	dst_release(&rt->dst);
	goto tx_error;
}
Exemplo n.º 9
0
static int get_tpkt_data(struct sk_buff *skb, unsigned int protoff,
			 struct nf_conn *ct, enum ip_conntrack_info ctinfo,
			 unsigned char **data, int *datalen, int *dataoff)
{
	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
	int dir = CTINFO2DIR(ctinfo);
	const struct tcphdr *th;
	struct tcphdr _tcph;
	int tcpdatalen;
	int tcpdataoff;
	unsigned char *tpkt;
	int tpktlen;
	int tpktoff;

#ifdef CONFIG_HTC_NETWORK_MODIFY
	if (IS_ERR(info) || (!info))
		printk(KERN_ERR "[NET] info is NULL in %s!\n", __func__);
#endif

	
	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
	if (th == NULL)
		return 0;

	
	tcpdataoff = protoff + th->doff * 4;

	
	tcpdatalen = skb->len - tcpdataoff;
	if (tcpdatalen <= 0)	
		goto clear_out;

	if (*data == NULL) {	
		
		tpkt = skb_header_pointer(skb, tcpdataoff, tcpdatalen,
					  h323_buffer);
		BUG_ON(tpkt == NULL);

		
		if (tcpdatalen < 4 || tpkt[0] != 0x03 || tpkt[1] != 0) {
			
			if (info->tpkt_len[dir] > 0) {
				pr_debug("nf_ct_h323: previous packet "
					 "indicated separate TPKT data of %hu "
					 "bytes\n", info->tpkt_len[dir]);
				if (info->tpkt_len[dir] <= tcpdatalen) {
					*data = tpkt;
					*datalen = info->tpkt_len[dir];
					*dataoff = 0;
					goto out;
				}

				
				pr_debug("nf_ct_h323: fragmented TPKT\n");
				goto clear_out;
			}

			
			return 0;
		}
		tpktoff = 0;
	} else {		
		tpktoff = *dataoff + *datalen;
		tcpdatalen -= tpktoff;
		if (tcpdatalen <= 4)	
			goto clear_out;
		tpkt = *data + *datalen;

		
		if (tpkt[0] != 0x03 || tpkt[1] != 0)
			goto clear_out;
	}

	
	tpktlen = tpkt[2] * 256 + tpkt[3];
	if (tpktlen < 4)
		goto clear_out;
	if (tpktlen > tcpdatalen) {
		if (tcpdatalen == 4) {	
			
			pr_debug("nf_ct_h323: separate TPKT header indicates "
				 "there will be TPKT data of %hu bytes\n",
				 tpktlen - 4);
			info->tpkt_len[dir] = tpktlen - 4;
			return 0;
		}

		pr_debug("nf_ct_h323: incomplete TPKT (fragmented?)\n");
		goto clear_out;
	}

	
	*data = tpkt + 4;
	*datalen = tpktlen - 4;
	*dataoff = tpktoff + 4;

      out:
	
	info->tpkt_len[dir] = 0;
	return 1;

      clear_out:
	info->tpkt_len[dir] = 0;
	return 0;
}
Exemplo n.º 10
0
static bool
ipv6header_mt6(const struct sk_buff *skb, const struct net_device *in,
               const struct net_device *out, const struct xt_match *match,
               const void *matchinfo, int offset, unsigned int protoff,
               bool *hotdrop)
{
	const struct ip6t_ipv6header_info *info = matchinfo;
	unsigned int temp;
	int len;
	u8 nexthdr;
	unsigned int ptr;

	/* Make sure this isn't an evil packet */

	/* type of the 1st exthdr */
	nexthdr = ipv6_hdr(skb)->nexthdr;
	/* pointer to the 1st exthdr */
	ptr = sizeof(struct ipv6hdr);
	/* available length */
	len = skb->len - ptr;
	temp = 0;

	while (ip6t_ext_hdr(nexthdr)) {
		struct ipv6_opt_hdr _hdr, *hp;
		int hdrlen;

		/* Is there enough space for the next ext header? */
		if (len < (int)sizeof(struct ipv6_opt_hdr))
			return false;
		/* No more exthdr -> evaluate */
		if (nexthdr == NEXTHDR_NONE) {
			temp |= MASK_NONE;
			break;
		}
		/* ESP -> evaluate */
		if (nexthdr == NEXTHDR_ESP) {
			temp |= MASK_ESP;
			break;
		}

		hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
		BUG_ON(hp == NULL);

		/* Calculate the header length */
		if (nexthdr == NEXTHDR_FRAGMENT)
			hdrlen = 8;
		else if (nexthdr == NEXTHDR_AUTH)
			hdrlen = (hp->hdrlen + 2) << 2;
		else
			hdrlen = ipv6_optlen(hp);

		/* set the flag */
		switch (nexthdr) {
		case NEXTHDR_HOP:
			temp |= MASK_HOPOPTS;
			break;
		case NEXTHDR_ROUTING:
			temp |= MASK_ROUTING;
			break;
		case NEXTHDR_FRAGMENT:
			temp |= MASK_FRAGMENT;
			break;
		case NEXTHDR_AUTH:
			temp |= MASK_AH;
			break;
		case NEXTHDR_DEST:
			temp |= MASK_DSTOPTS;
			break;
		default:
			return false;
			break;
		}

		nexthdr = hp->nexthdr;
		len -= hdrlen;
		ptr += hdrlen;
		if (ptr > skb->len)
			break;
	}

	if (nexthdr != NEXTHDR_NONE && nexthdr != NEXTHDR_ESP)
		temp |= MASK_PROTO;

	if (info->modeflag)
		return !((temp ^ info->matchflags ^ info->invflags)
			 & info->matchflags);
	else {
		if (info->invflags)
			return temp != info->matchflags;
		else
			return temp == info->matchflags;
	}
}
Exemplo n.º 11
0
/*
 *      NAT transmitter (only for outside-to-inside nat forwarding)
 *      Not used for related ICMP
 */
int
ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
	       struct ip_vs_protocol *pp)
{
	struct rtable *rt;		/* Route to the other host */
	int mtu;
	struct iphdr *iph = ip_hdr(skb);
	int local;

	EnterFunction(10);

	/* check if it is a connection of no-client-port */
	if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
		__be16 _pt, *p;
		p = skb_header_pointer(skb, iph->ihl*4, sizeof(_pt), &_pt);
		if (p == NULL)
			goto tx_error;
		ip_vs_conn_fill_cport(cp, *p);
		IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
	}

	if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
				      RT_TOS(iph->tos),
				      IP_VS_RT_MODE_LOCAL |
					IP_VS_RT_MODE_NON_LOCAL |
					IP_VS_RT_MODE_RDR, NULL)))
		goto tx_error_icmp;
	local = rt->rt_flags & RTCF_LOCAL;
	/*
	 * Avoid duplicate tuple in reply direction for NAT traffic
	 * to local address when connection is sync-ed
	 */
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
	if (cp->flags & IP_VS_CONN_F_SYNC && local) {
		enum ip_conntrack_info ctinfo;
		struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);

		if (ct && !nf_ct_is_untracked(ct)) {
			IP_VS_DBG_RL_PKT(10, AF_INET, pp, skb, 0,
					 "ip_vs_nat_xmit(): "
					 "stopping DNAT to local address");
			goto tx_error_put;
		}
	}
#endif

	/* From world but DNAT to loopback address? */
	if (local && ipv4_is_loopback(cp->daddr.ip) &&
	    rt_is_input_route(skb_rtable(skb))) {
		IP_VS_DBG_RL_PKT(1, AF_INET, pp, skb, 0, "ip_vs_nat_xmit(): "
				 "stopping DNAT to loopback address");
		goto tx_error_put;
	}

	/* MTU checking */
	mtu = dst_mtu(&rt->dst);
	if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF)) &&
	    !skb_is_gso(skb)) {
		icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
		IP_VS_DBG_RL_PKT(0, AF_INET, pp, skb, 0,
				 "ip_vs_nat_xmit(): frag needed for");
		goto tx_error_put;
	}

	/* copy-on-write the packet before mangling it */
	if (!skb_make_writable(skb, sizeof(struct iphdr)))
		goto tx_error_put;

	if (skb_cow(skb, rt->dst.dev->hard_header_len))
		goto tx_error_put;

	/* mangle the packet */
	if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp))
		goto tx_error_put;
	ip_hdr(skb)->daddr = cp->daddr.ip;
	ip_send_check(ip_hdr(skb));

	if (!local) {
		/* drop old route */
		skb_dst_drop(skb);
		skb_dst_set(skb, &rt->dst);
	} else {
		ip_rt_put(rt);
		/*
		 * Some IPv4 replies get local address from routes,
		 * not from iph, so while we DNAT after routing
		 * we need this second input/output route.
		 */
		if (!__ip_vs_reroute_locally(skb))
			goto tx_error;
	}

	IP_VS_DBG_PKT(10, AF_INET, pp, skb, 0, "After DNAT");

	/* FIXME: when application helper enlarges the packet and the length
	   is larger than the MTU of outgoing device, there will be still
	   MTU problem. */

	/* Another hack: avoid icmp_send in ip_fragment */
	skb->local_df = 1;

	IP_VS_XMIT_NAT(NFPROTO_IPV4, skb, cp, local);

	LeaveFunction(10);
	return NF_STOLEN;

  tx_error_icmp:
	dst_link_failure(skb);
  tx_error:
	kfree_skb(skb);
	LeaveFunction(10);
	return NF_STOLEN;
  tx_error_put:
	ip_rt_put(rt);
	goto tx_error;
}
Exemplo n.º 12
0
/* Send RST reply */
static void send_reset(struct sk_buff *oldskb, int hook)
{
	struct sk_buff *nskb;
	const struct iphdr *oiph;
	struct iphdr *niph;
	const struct tcphdr *oth;
	struct tcphdr _otcph, *tcph;

	/* IP header checks: fragment. */
	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
		return;

	oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
				 sizeof(_otcph), &_otcph);
	if (oth == NULL)
		return;

	/* No RST for RST. */
	if (oth->rst)
		return;

	if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
		return;

	/* Check checksum */
	if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
		return;
	oiph = ip_hdr(oldskb);

	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
			 LL_MAX_HEADER, GFP_ATOMIC);
	if (!nskb)
		return;

	skb_reserve(nskb, LL_MAX_HEADER);

	skb_reset_network_header(nskb);
	niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
	niph->version	= 4;
	niph->ihl	= sizeof(struct iphdr) / 4;
	niph->tos	= 0;
	niph->id	= 0;
	niph->frag_off	= htons(IP_DF);
	niph->protocol	= IPPROTO_TCP;
	niph->check	= 0;
	niph->saddr	= oiph->daddr;
	niph->daddr	= oiph->saddr;

	skb_reset_transport_header(nskb);
	tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
	memset(tcph, 0, sizeof(*tcph));
	tcph->source	= oth->dest;
	tcph->dest	= oth->source;
	tcph->doff	= sizeof(struct tcphdr) / 4;

	if (oth->ack)
		tcph->seq = oth->ack_seq;
	else {
		tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
				      oldskb->len - ip_hdrlen(oldskb) -
				      (oth->doff << 2));
		tcph->ack = 1;
	}

	tcph->rst	= 1;
	tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), niph->saddr,
				    niph->daddr, 0);
	nskb->ip_summed = CHECKSUM_PARTIAL;
	nskb->csum_start = (unsigned char *)tcph - nskb->head;
	nskb->csum_offset = offsetof(struct tcphdr, check);

	/* ip_route_me_harder expects skb->dst to be set */
	skb_dst_set_noref(nskb, skb_dst(oldskb));

	nskb->protocol = htons(ETH_P_IP);
	if (ip_route_me_harder(nskb, RTN_UNSPEC))
		goto free_nskb;

	niph->ttl	= ip4_dst_hoplimit(skb_dst(nskb));

	/* "Never happens" */
	if (nskb->len > dst_mtu(skb_dst(nskb)))
		goto free_nskb;

	nf_ct_attach(nskb, oldskb);

	ip_local_out(nskb);
	return;

 free_nskb:
	kfree_skb(nskb);
}
Exemplo n.º 13
0
static int
tcp_match(const struct sk_buff *skb,
	  const struct net_device *in,
	  const struct net_device *out,
	  const struct xt_match *match,
	  const void *matchinfo,
	  int offset,
	  unsigned int protoff,
	  int *hotdrop)
{
	struct tcphdr _tcph, *th;
	const struct xt_tcp *tcpinfo = matchinfo;

	if (offset) {
		/* To quote Alan:

		   Don't allow a fragment of TCP 8 bytes in. Nobody normal
		   causes this. Its a cracker trying to break in by doing a
		   flag overwrite to pass the direction checks.
		*/
		if (offset == 1) {
			duprintf("Dropping evil TCP offset=1 frag.\n");
			*hotdrop = 1;
		}
		/* Must not be a fragment. */
		return 0;
	}

#define FWINVTCP(bool,invflg) ((bool) ^ !!(tcpinfo->invflags & invflg))

	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
	if (th == NULL) {
		/* We've been asked to examine this packet, and we
		   can't.  Hence, no choice but to drop. */
		duprintf("Dropping evil TCP offset=0 tinygram.\n");
		*hotdrop = 1;
		return 0;
	}

	if (!port_match(tcpinfo->spts[0], tcpinfo->spts[1],
			ntohs(th->source),
			!!(tcpinfo->invflags & XT_TCP_INV_SRCPT)))
		return 0;
	if (!port_match(tcpinfo->dpts[0], tcpinfo->dpts[1],
			ntohs(th->dest),
			!!(tcpinfo->invflags & XT_TCP_INV_DSTPT)))
		return 0;
	if (!FWINVTCP((((unsigned char *)th)[13] & tcpinfo->flg_mask)
		      == tcpinfo->flg_cmp,
		      XT_TCP_INV_FLAGS))
		return 0;
	if (tcpinfo->option) {
		if (th->doff * 4 < sizeof(_tcph)) {
			*hotdrop = 1;
			return 0;
		}
		if (!tcp_find_option(tcpinfo->option, skb, protoff,
				     th->doff*4 - sizeof(_tcph),
				     tcpinfo->invflags & XT_TCP_INV_OPTION,
				     hotdrop))
			return 0;
	}
	return 1;
}
Exemplo n.º 14
0
bool
synproxy_parse_options(const struct sk_buff *skb, unsigned int doff,
		       const struct tcphdr *th, struct synproxy_options *opts)
{
	int length = (th->doff * 4) - sizeof(*th);
	u8 buf[40], *ptr;

	ptr = skb_header_pointer(skb, doff + sizeof(*th), length, buf);
	if (ptr == NULL)
		return false;

	opts->options = 0;
	while (length > 0) {
		int opcode = *ptr++;
		int opsize;

		switch (opcode) {
		case TCPOPT_EOL:
			return true;
		case TCPOPT_NOP:
			length--;
			continue;
		default:
			opsize = *ptr++;
			if (opsize < 2)
				return true;
			if (opsize > length)
				return true;

			switch (opcode) {
			case TCPOPT_MSS:
				if (opsize == TCPOLEN_MSS) {
					opts->mss = get_unaligned_be16(ptr);
					opts->options |= XT_SYNPROXY_OPT_MSS;
				}
				break;
			case TCPOPT_WINDOW:
				if (opsize == TCPOLEN_WINDOW) {
					opts->wscale = *ptr;
					if (opts->wscale > 14)
						opts->wscale = 14;
					opts->options |= XT_SYNPROXY_OPT_WSCALE;
				}
				break;
			case TCPOPT_TIMESTAMP:
				if (opsize == TCPOLEN_TIMESTAMP) {
					opts->tsval = get_unaligned_be32(ptr);
					opts->tsecr = get_unaligned_be32(ptr + 4);
					opts->options |= XT_SYNPROXY_OPT_TIMESTAMP;
				}
				break;
			case TCPOPT_SACK_PERM:
				if (opsize == TCPOLEN_SACK_PERM)
					opts->options |= XT_SYNPROXY_OPT_SACK_PERM;
				break;
			}

			ptr += opsize - 2;
			length -= opsize;
		}
	}
	return true;
}
Exemplo n.º 15
0
/* One level of recursion won't kill us */
static void dump_ipv4_packet(struct sbuff *m,
			const struct nf_loginfo *info,
			const struct sk_buff *skb,
			unsigned int iphoff)
{
	struct iphdr _iph;
	const struct iphdr *ih;
	unsigned int logflags;

	if (info->type == NF_LOG_TYPE_LOG)
		logflags = info->u.log.logflags;
	else
		logflags = NF_LOG_MASK;

	ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
	if (ih == NULL) {
		sb_add(m, "TRUNCATED");
		return;
	}

	/* Important fields:
	 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
	/* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
	sb_add(m, "SRC=%pI4 DST=%pI4 ",
	       &ih->saddr, &ih->daddr);

	/* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
	sb_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
	       ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
	       ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));

	/* Max length: 6 "CE DF MF " */
	if (ntohs(ih->frag_off) & IP_CE)
		sb_add(m, "CE ");
	if (ntohs(ih->frag_off) & IP_DF)
		sb_add(m, "DF ");
	if (ntohs(ih->frag_off) & IP_MF)
		sb_add(m, "MF ");

	/* Max length: 11 "FRAG:65535 " */
	if (ntohs(ih->frag_off) & IP_OFFSET)
		sb_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);

	if ((logflags & XT_LOG_IPOPT) &&
	    ih->ihl * 4 > sizeof(struct iphdr)) {
		const unsigned char *op;
		unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
		unsigned int i, optsize;

		optsize = ih->ihl * 4 - sizeof(struct iphdr);
		op = skb_header_pointer(skb, iphoff+sizeof(_iph),
					optsize, _opt);
		if (op == NULL) {
			sb_add(m, "TRUNCATED");
			return;
		}

		/* Max length: 127 "OPT (" 15*4*2chars ") " */
		sb_add(m, "OPT (");
		for (i = 0; i < optsize; i++)
			sb_add(m, "%02X", op[i]);
		sb_add(m, ") ");
	}

	switch (ih->protocol) {
	case IPPROTO_TCP:
		if (dump_tcp_header(m, skb, ih->protocol,
				    ntohs(ih->frag_off) & IP_OFFSET,
				    iphoff+ih->ihl*4, logflags))
			return;
		break;
	case IPPROTO_UDP:
	case IPPROTO_UDPLITE:
		if (dump_udp_header(m, skb, ih->protocol,
				    ntohs(ih->frag_off) & IP_OFFSET,
				    iphoff+ih->ihl*4))
			return;
		break;
	case IPPROTO_ICMP: {
		struct icmphdr _icmph;
		const struct icmphdr *ich;
		static const size_t required_len[NR_ICMP_TYPES+1]
			= { [ICMP_ECHOREPLY] = 4,
			    [ICMP_DEST_UNREACH]
			    = 8 + sizeof(struct iphdr),
			    [ICMP_SOURCE_QUENCH]
			    = 8 + sizeof(struct iphdr),
			    [ICMP_REDIRECT]
			    = 8 + sizeof(struct iphdr),
			    [ICMP_ECHO] = 4,
			    [ICMP_TIME_EXCEEDED]
			    = 8 + sizeof(struct iphdr),
			    [ICMP_PARAMETERPROB]
			    = 8 + sizeof(struct iphdr),
			    [ICMP_TIMESTAMP] = 20,
			    [ICMP_TIMESTAMPREPLY] = 20,
			    [ICMP_ADDRESS] = 12,
			    [ICMP_ADDRESSREPLY] = 12 };

		/* Max length: 11 "PROTO=ICMP " */
		sb_add(m, "PROTO=ICMP ");

		if (ntohs(ih->frag_off) & IP_OFFSET)
			break;

		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
		ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
					 sizeof(_icmph), &_icmph);
		if (ich == NULL) {
			sb_add(m, "INCOMPLETE [%u bytes] ",
			       skb->len - iphoff - ih->ihl*4);
			break;
		}

		/* Max length: 18 "TYPE=255 CODE=255 " */
		sb_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code);

		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
		if (ich->type <= NR_ICMP_TYPES &&
		    required_len[ich->type] &&
		    skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
			sb_add(m, "INCOMPLETE [%u bytes] ",
			       skb->len - iphoff - ih->ihl*4);
			break;
		}

		switch (ich->type) {
		case ICMP_ECHOREPLY:
		case ICMP_ECHO:
			/* Max length: 19 "ID=65535 SEQ=65535 " */
			sb_add(m, "ID=%u SEQ=%u ",
			       ntohs(ich->un.echo.id),
			       ntohs(ich->un.echo.sequence));
			break;

		case ICMP_PARAMETERPROB:
			/* Max length: 14 "PARAMETER=255 " */
			sb_add(m, "PARAMETER=%u ",
			       ntohl(ich->un.gateway) >> 24);
			break;
		case ICMP_REDIRECT:
			/* Max length: 24 "GATEWAY=255.255.255.255 " */
			sb_add(m, "GATEWAY=%pI4 ", &ich->un.gateway);
			/* Fall through */
		case ICMP_DEST_UNREACH:
		case ICMP_SOURCE_QUENCH:
		case ICMP_TIME_EXCEEDED:
			/* Max length: 3+maxlen */
			if (!iphoff) { /* Only recurse once. */
				sb_add(m, "[");
				dump_ipv4_packet(m, info, skb,
					    iphoff + ih->ihl*4+sizeof(_icmph));
				sb_add(m, "] ");
			}

			/* Max length: 10 "MTU=65535 " */
			if (ich->type == ICMP_DEST_UNREACH &&
			    ich->code == ICMP_FRAG_NEEDED)
				sb_add(m, "MTU=%u ", ntohs(ich->un.frag.mtu));
		}
		break;
	}
	/* Max Length */
	case IPPROTO_AH: {
		struct ip_auth_hdr _ahdr;
		const struct ip_auth_hdr *ah;

		if (ntohs(ih->frag_off) & IP_OFFSET)
			break;

		/* Max length: 9 "PROTO=AH " */
		sb_add(m, "PROTO=AH ");

		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
		ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
					sizeof(_ahdr), &_ahdr);
		if (ah == NULL) {
			sb_add(m, "INCOMPLETE [%u bytes] ",
			       skb->len - iphoff - ih->ihl*4);
			break;
		}

		/* Length: 15 "SPI=0xF1234567 " */
		sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
		break;
	}
	case IPPROTO_ESP: {
		struct ip_esp_hdr _esph;
		const struct ip_esp_hdr *eh;

		/* Max length: 10 "PROTO=ESP " */
		sb_add(m, "PROTO=ESP ");

		if (ntohs(ih->frag_off) & IP_OFFSET)
			break;

		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
		eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
					sizeof(_esph), &_esph);
		if (eh == NULL) {
			sb_add(m, "INCOMPLETE [%u bytes] ",
			       skb->len - iphoff - ih->ihl*4);
			break;
		}

		/* Length: 15 "SPI=0xF1234567 " */
		sb_add(m, "SPI=0x%x ", ntohl(eh->spi));
		break;
	}
	/* Max length: 10 "PROTO 255 " */
	default:
		sb_add(m, "PROTO=%u ", ih->protocol);
	}

	/* Max length: 15 "UID=4294967295 " */
	if ((logflags & XT_LOG_UID) && !iphoff)
		dump_sk_uid_gid(m, skb->sk);

	/* Max length: 16 "MARK=0xFFFFFFFF " */
	if (!iphoff && skb->mark)
		sb_add(m, "MARK=0x%x ", skb->mark);

	/* Proto    Max log string length */
	/* IP:      40+46+6+11+127 = 230 */
	/* TCP:     10+max(25,20+30+13+9+32+11+127) = 252 */
	/* UDP:     10+max(25,20) = 35 */
	/* UDPLITE: 14+max(25,20) = 39 */
	/* ICMP:    11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
	/* ESP:     10+max(25)+15 = 50 */
	/* AH:      9+max(25)+15 = 49 */
	/* unknown: 10 */

	/* (ICMP allows recursion one level deep) */
	/* maxlen =  IP + ICMP +  IP + max(TCP,UDP,ICMP,unknown) */
	/* maxlen = 230+   91  + 230 + 252 = 803 */
}
Exemplo n.º 16
0
static bool
ebt_arp_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct ebt_arp_info *info = par->matchinfo;
	const struct arphdr *ah;
	struct arphdr _arph;

	ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
	if (ah == NULL)
		return false;
	if (info->bitmask & EBT_ARP_OPCODE && FWINV(info->opcode !=
	   ah->ar_op, EBT_ARP_OPCODE))
		return false;
	if (info->bitmask & EBT_ARP_HTYPE && FWINV(info->htype !=
	   ah->ar_hrd, EBT_ARP_HTYPE))
		return false;
	if (info->bitmask & EBT_ARP_PTYPE && FWINV(info->ptype !=
	   ah->ar_pro, EBT_ARP_PTYPE))
		return false;

	if (info->bitmask & (EBT_ARP_SRC_IP | EBT_ARP_DST_IP | EBT_ARP_GRAT)) {
		const __be32 *sap, *dap;
		__be32 saddr, daddr;

		if (ah->ar_pln != sizeof(__be32) || ah->ar_pro != htons(ETH_P_IP))
			return false;
		sap = skb_header_pointer(skb, sizeof(struct arphdr) +
					ah->ar_hln, sizeof(saddr),
					&saddr);
		if (sap == NULL)
			return false;
		dap = skb_header_pointer(skb, sizeof(struct arphdr) +
					2*ah->ar_hln+sizeof(saddr),
					sizeof(daddr), &daddr);
		if (dap == NULL)
			return false;
		if (info->bitmask & EBT_ARP_SRC_IP &&
		    FWINV(info->saddr != (*sap & info->smsk), EBT_ARP_SRC_IP))
			return false;
		if (info->bitmask & EBT_ARP_DST_IP &&
		    FWINV(info->daddr != (*dap & info->dmsk), EBT_ARP_DST_IP))
			return false;
		if (info->bitmask & EBT_ARP_GRAT &&
		    FWINV(*dap != *sap, EBT_ARP_GRAT))
			return false;
	}

	if (info->bitmask & (EBT_ARP_SRC_MAC | EBT_ARP_DST_MAC)) {
		const unsigned char *mp;
		unsigned char _mac[ETH_ALEN];
		uint8_t verdict, i;

		if (ah->ar_hln != ETH_ALEN || ah->ar_hrd != htons(ARPHRD_ETHER))
			return false;
		if (info->bitmask & EBT_ARP_SRC_MAC) {
			mp = skb_header_pointer(skb, sizeof(struct arphdr),
						sizeof(_mac), &_mac);
			if (mp == NULL)
				return false;
			verdict = 0;
			for (i = 0; i < 6; i++)
				verdict |= (mp[i] ^ info->smaddr[i]) &
				       info->smmsk[i];
			if (FWINV(verdict != 0, EBT_ARP_SRC_MAC))
				return false;
		}

		if (info->bitmask & EBT_ARP_DST_MAC) {
			mp = skb_header_pointer(skb, sizeof(struct arphdr) +
						ah->ar_hln + ah->ar_pln,
						sizeof(_mac), &_mac);
			if (mp == NULL)
				return false;
			verdict = 0;
			for (i = 0; i < 6; i++)
				verdict |= (mp[i] ^ info->dmaddr[i]) &
					info->dmmsk[i];
			if (FWINV(verdict != 0, EBT_ARP_DST_MAC))
				return false;
		}
	}

	return true;
}
Exemplo n.º 17
0
/* One level of recursion won't kill us */
static void dump_ipv6_packet(struct sbuff *m,
			const struct nf_loginfo *info,
			const struct sk_buff *skb, unsigned int ip6hoff,
			int recurse)
{
	u_int8_t currenthdr;
	int fragment;
	struct ipv6hdr _ip6h;
	const struct ipv6hdr *ih;
	unsigned int ptr;
	unsigned int hdrlen = 0;
	unsigned int logflags;

	if (info->type == NF_LOG_TYPE_LOG)
		logflags = info->u.log.logflags;
	else
		logflags = NF_LOG_MASK;

	ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
	if (ih == NULL) {
		sb_add(m, "TRUNCATED");
		return;
	}

	/* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
	sb_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);

	/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
	sb_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
	       ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
	       (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
	       ih->hop_limit,
	       (ntohl(*(__be32 *)ih) & 0x000fffff));

	fragment = 0;
	ptr = ip6hoff + sizeof(struct ipv6hdr);
	currenthdr = ih->nexthdr;
	while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
		struct ipv6_opt_hdr _hdr;
		const struct ipv6_opt_hdr *hp;

		hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
		if (hp == NULL) {
			sb_add(m, "TRUNCATED");
			return;
		}

		/* Max length: 48 "OPT (...) " */
		if (logflags & XT_LOG_IPOPT)
			sb_add(m, "OPT ( ");

		switch (currenthdr) {
		case IPPROTO_FRAGMENT: {
			struct frag_hdr _fhdr;
			const struct frag_hdr *fh;

			sb_add(m, "FRAG:");
			fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
						&_fhdr);
			if (fh == NULL) {
				sb_add(m, "TRUNCATED ");
				return;
			}

			/* Max length: 6 "65535 " */
			sb_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);

			/* Max length: 11 "INCOMPLETE " */
			if (fh->frag_off & htons(0x0001))
				sb_add(m, "INCOMPLETE ");

			sb_add(m, "ID:%08x ", ntohl(fh->identification));

			if (ntohs(fh->frag_off) & 0xFFF8)
				fragment = 1;

			hdrlen = 8;

			break;
		}
		case IPPROTO_DSTOPTS:
		case IPPROTO_ROUTING:
		case IPPROTO_HOPOPTS:
			if (fragment) {
				if (logflags & XT_LOG_IPOPT)
					sb_add(m, ")");
				return;
			}
			hdrlen = ipv6_optlen(hp);
			break;
		/* Max Length */
		case IPPROTO_AH:
			if (logflags & XT_LOG_IPOPT) {
				struct ip_auth_hdr _ahdr;
				const struct ip_auth_hdr *ah;

				/* Max length: 3 "AH " */
				sb_add(m, "AH ");

				if (fragment) {
					sb_add(m, ")");
					return;
				}

				ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
							&_ahdr);
				if (ah == NULL) {
					/*
					 * Max length: 26 "INCOMPLETE [65535
					 *  bytes] )"
					 */
					sb_add(m, "INCOMPLETE [%u bytes] )",
					       skb->len - ptr);
					return;
				}

				/* Length: 15 "SPI=0xF1234567 */
				sb_add(m, "SPI=0x%x ", ntohl(ah->spi));

			}

			hdrlen = (hp->hdrlen+2)<<2;
			break;
		case IPPROTO_ESP:
			if (logflags & XT_LOG_IPOPT) {
				struct ip_esp_hdr _esph;
				const struct ip_esp_hdr *eh;

				/* Max length: 4 "ESP " */
				sb_add(m, "ESP ");

				if (fragment) {
					sb_add(m, ")");
					return;
				}

				/*
				 * Max length: 26 "INCOMPLETE [65535 bytes] )"
				 */
				eh = skb_header_pointer(skb, ptr, sizeof(_esph),
							&_esph);
				if (eh == NULL) {
					sb_add(m, "INCOMPLETE [%u bytes] )",
					       skb->len - ptr);
					return;
				}

				/* Length: 16 "SPI=0xF1234567 )" */
				sb_add(m, "SPI=0x%x )", ntohl(eh->spi));

			}
			return;
		default:
			/* Max length: 20 "Unknown Ext Hdr 255" */
			sb_add(m, "Unknown Ext Hdr %u", currenthdr);
			return;
		}
		if (logflags & XT_LOG_IPOPT)
			sb_add(m, ") ");

		currenthdr = hp->nexthdr;
		ptr += hdrlen;
	}

	switch (currenthdr) {
	case IPPROTO_TCP:
		if (dump_tcp_header(m, skb, currenthdr, fragment, ptr,
		    logflags))
			return;
		break;
	case IPPROTO_UDP:
	case IPPROTO_UDPLITE:
		if (dump_udp_header(m, skb, currenthdr, fragment, ptr))
			return;
		break;
	case IPPROTO_ICMPV6: {
		struct icmp6hdr _icmp6h;
		const struct icmp6hdr *ic;

		/* Max length: 13 "PROTO=ICMPv6 " */
		sb_add(m, "PROTO=ICMPv6 ");

		if (fragment)
			break;

		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
		ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
		if (ic == NULL) {
			sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
			return;
		}

		/* Max length: 18 "TYPE=255 CODE=255 " */
		sb_add(m, "TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);

		switch (ic->icmp6_type) {
		case ICMPV6_ECHO_REQUEST:
		case ICMPV6_ECHO_REPLY:
			/* Max length: 19 "ID=65535 SEQ=65535 " */
			sb_add(m, "ID=%u SEQ=%u ",
				ntohs(ic->icmp6_identifier),
				ntohs(ic->icmp6_sequence));
			break;
		case ICMPV6_MGM_QUERY:
		case ICMPV6_MGM_REPORT:
		case ICMPV6_MGM_REDUCTION:
			break;

		case ICMPV6_PARAMPROB:
			/* Max length: 17 "POINTER=ffffffff " */
			sb_add(m, "POINTER=%08x ", ntohl(ic->icmp6_pointer));
			/* Fall through */
		case ICMPV6_DEST_UNREACH:
		case ICMPV6_PKT_TOOBIG:
		case ICMPV6_TIME_EXCEED:
			/* Max length: 3+maxlen */
			if (recurse) {
				sb_add(m, "[");
				dump_ipv6_packet(m, info, skb,
					    ptr + sizeof(_icmp6h), 0);
				sb_add(m, "] ");
			}

			/* Max length: 10 "MTU=65535 " */
			if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
				sb_add(m, "MTU=%u ", ntohl(ic->icmp6_mtu));
		}
		break;
	}
	/* Max length: 10 "PROTO=255 " */
	default:
		sb_add(m, "PROTO=%u ", currenthdr);
	}

	/* Max length: 15 "UID=4294967295 " */
	if ((logflags & XT_LOG_UID) && recurse)
		dump_sk_uid_gid(m, skb->sk);

	/* Max length: 16 "MARK=0xFFFFFFFF " */
	if (!recurse && skb->mark)
		sb_add(m, "MARK=0x%x ", skb->mark);
}
Exemplo n.º 18
0
/* Send RST reply */
static void send_reset(struct sk_buff *oldskb, int hook)
{
	struct sk_buff *nskb;
	const struct iphdr *oiph;
	struct iphdr *niph;
	const struct tcphdr *oth;
	struct tcphdr _otcph, *tcph;
	unsigned int addr_type;

	/* IP header checks: fragment. */
	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
		return;

	oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
				 sizeof(_otcph), &_otcph);
	if (oth == NULL)
		return;

	/* No RST for RST. */
	if (oth->rst)
		return;

	/* Check checksum */
	if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
		return;
	oiph = ip_hdr(oldskb);

	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
			 LL_MAX_HEADER, GFP_ATOMIC);
	if (!nskb)
		return;

	skb_reserve(nskb, LL_MAX_HEADER);

	skb_reset_network_header(nskb);
	niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
	niph->version	= 4;
	niph->ihl	= sizeof(struct iphdr) / 4;
	niph->tos	= 0;
	niph->id	= 0;
	niph->frag_off	= htons(IP_DF);
	niph->protocol	= IPPROTO_TCP;
	niph->check	= 0;
	niph->saddr	= oiph->daddr;
	niph->daddr	= oiph->saddr;

	tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
	memset(tcph, 0, sizeof(*tcph));
	tcph->source	= oth->dest;
	tcph->dest	= oth->source;
	tcph->doff	= sizeof(struct tcphdr) / 4;

	if (oth->ack)
		tcph->seq = oth->ack_seq;
	else {
		tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
				      oldskb->len - ip_hdrlen(oldskb) -
				      (oth->doff << 2));
		tcph->ack = 1;
	}

	tcph->rst	= 1;
	tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), niph->saddr,
				    niph->daddr, 0);
	nskb->ip_summed = CHECKSUM_PARTIAL;
	nskb->csum_start = (unsigned char *)tcph - nskb->head;
	nskb->csum_offset = offsetof(struct tcphdr, check);

	addr_type = RTN_UNSPEC;
	if (hook != NF_INET_FORWARD
#ifdef CONFIG_BRIDGE_NETFILTER
	    || (nskb->nf_bridge && nskb->nf_bridge->mask & BRNF_BRIDGED)
#endif
	   )
		addr_type = RTN_LOCAL;

	/* ip_route_me_harder expects skb->dst to be set */
	skb_dst_set_noref(nskb, skb_dst(oldskb));

	if (ip_route_me_harder(nskb, addr_type))
		goto free_nskb;

	niph->ttl	= dst_metric(skb_dst(nskb), RTAX_HOPLIMIT);

	/* "Never happens" */
	if (nskb->len > dst_mtu(skb_dst(nskb)))
		goto free_nskb;

	nf_ct_attach(nskb, oldskb);

	ip_local_out(nskb);
	return;

 free_nskb:
	kfree_skb(nskb);
}
static int help(struct sk_buff *skb,
		unsigned int protoff,
		struct nf_conn *ct,
		enum ip_conntrack_info ctinfo)
{
	unsigned int dataoff, datalen;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	void *sb_ptr;
	int ret = NF_ACCEPT;
	int dir = CTINFO2DIR(ctinfo);
	struct nf_ct_sane_master *ct_sane_info;
	struct nf_conntrack_expect *exp;
	struct nf_conntrack_tuple *tuple;
	struct sane_request *req;
	struct sane_reply_net_start *reply;

	ct_sane_info = &nfct_help(ct)->help.ct_sane_info;
	/* Until there's been traffic both ways, don't look in packets. */
	if (ctinfo != IP_CT_ESTABLISHED &&
	    ctinfo != IP_CT_ESTABLISHED_REPLY)
		return NF_ACCEPT;

	/* Not a full tcp header? */
	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
	if (th == NULL)
		return NF_ACCEPT;

	/* No data? */
	dataoff = protoff + th->doff * 4;
	if (dataoff >= skb->len)
		return NF_ACCEPT;

	datalen = skb->len - dataoff;

	spin_lock_bh(&nf_sane_lock);
	sb_ptr = skb_header_pointer(skb, dataoff, datalen, sane_buffer);
	BUG_ON(sb_ptr == NULL);

	if (dir == IP_CT_DIR_ORIGINAL) {
		if (datalen != sizeof(struct sane_request))
			goto out;

		req = sb_ptr;
		if (req->RPC_code != htonl(SANE_NET_START)) {
			/* Not an interesting command */
			ct_sane_info->state = SANE_STATE_NORMAL;
			goto out;
		}

		/* We're interested in the next reply */
		ct_sane_info->state = SANE_STATE_START_REQUESTED;
		goto out;
	}

	/* Is it a reply to an uninteresting command? */
	if (ct_sane_info->state != SANE_STATE_START_REQUESTED)
		goto out;

	/* It's a reply to SANE_NET_START. */
	ct_sane_info->state = SANE_STATE_NORMAL;

	if (datalen < sizeof(struct sane_reply_net_start)) {
		pr_debug("nf_ct_sane: NET_START reply too short\n");
		goto out;
	}

	reply = sb_ptr;
	if (reply->status != htonl(SANE_STATUS_SUCCESS)) {
		/* saned refused the command */
		pr_debug("nf_ct_sane: unsuccessful SANE_STATUS = %u\n",
			 ntohl(reply->status));
		goto out;
	}

	/* Invalid saned reply? Ignore it. */
	if (reply->zero != 0)
		goto out;

	exp = nf_ct_expect_alloc(ct);
	if (exp == NULL) {
		ret = NF_DROP;
		goto out;
	}

	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
			  &tuple->src.u3, &tuple->dst.u3,
			  IPPROTO_TCP, NULL, &reply->port);

	pr_debug("nf_ct_sane: expect: ");
	nf_ct_dump_tuple(&exp->tuple);

	/* Can't expect this?  Best to drop packet now. */
	if (nf_ct_expect_related(exp) != 0)
		ret = NF_DROP;

	nf_ct_expect_put(exp);

out:
	spin_unlock_bh(&nf_sane_lock);
	return ret;
}
Exemplo n.º 20
0
/* Returns verdict for packet, or -1 for invalid. */
static int tcp_packet(struct nf_conn *ct,
		      const struct sk_buff *skb,
		      unsigned int dataoff,
		      enum ip_conntrack_info ctinfo,
		      int pf,
		      unsigned int hooknum)
{
	struct nf_conntrack_tuple *tuple;
	enum tcp_conntrack new_state, old_state;
	enum ip_conntrack_dir dir;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	unsigned long timeout;
	unsigned int index;

	th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
	BUG_ON(th == NULL);

	write_lock_bh(&tcp_lock);
	old_state = ct->proto.tcp.state;
	dir = CTINFO2DIR(ctinfo);
	index = get_conntrack_index(th);
	new_state = tcp_conntracks[dir][index][old_state];
	tuple = &ct->tuplehash[dir].tuple;

	switch (new_state) {
	case TCP_CONNTRACK_SYN_SENT:
		if (old_state < TCP_CONNTRACK_TIME_WAIT)
			break;
		/* RFC 1122: "When a connection is closed actively,
		 * it MUST linger in TIME-WAIT state for a time 2xMSL
		 * (Maximum Segment Lifetime). However, it MAY accept
		 * a new SYN from the remote TCP to reopen the connection
		 * directly from TIME-WAIT state, if..."
		 * We ignore the conditions because we are in the
		 * TIME-WAIT state anyway.
		 *
		 * Handle aborted connections: we and the server
		 * think there is an existing connection but the client
		 * aborts it and starts a new one.
		 */
		if (((ct->proto.tcp.seen[dir].flags
		      | ct->proto.tcp.seen[!dir].flags)
		     & IP_CT_TCP_FLAG_CLOSE_INIT)
		    || (ct->proto.tcp.last_dir == dir
		        && ct->proto.tcp.last_index == TCP_RST_SET)) {
			/* Attempt to reopen a closed/aborted connection.
			 * Delete this connection and look up again. */
			write_unlock_bh(&tcp_lock);
			if (del_timer(&ct->timeout))
				ct->timeout.function((unsigned long)ct);
			return -NF_REPEAT;
		}
		/* Fall through */
	case TCP_CONNTRACK_IGNORE:
		/* Ignored packets:
		 *
		 * Our connection entry may be out of sync, so ignore
		 * packets which may signal the real connection between
		 * the client and the server.
		 *
		 * a) SYN in ORIGINAL
		 * b) SYN/ACK in REPLY
		 * c) ACK in reply direction after initial SYN in original.
		 *
		 * If the ignored packet is invalid, the receiver will send
		 * a RST we'll catch below.
		 */
		if (index == TCP_SYNACK_SET
		    && ct->proto.tcp.last_index == TCP_SYN_SET
		    && ct->proto.tcp.last_dir != dir
		    && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
			/* b) This SYN/ACK acknowledges a SYN that we earlier
			 * ignored as invalid. This means that the client and
			 * the server are both in sync, while the firewall is
			 * not. We kill this session and block the SYN/ACK so
			 * that the client cannot but retransmit its SYN and
			 * thus initiate a clean new session.
			 */
			write_unlock_bh(&tcp_lock);
			if (LOG_INVALID(IPPROTO_TCP))
				nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
					  "nf_ct_tcp: killing out of sync session ");
			if (del_timer(&ct->timeout))
				ct->timeout.function((unsigned long)ct);
			return -NF_DROP;
		}
		ct->proto.tcp.last_index = index;
		ct->proto.tcp.last_dir = dir;
		ct->proto.tcp.last_seq = ntohl(th->seq);
		ct->proto.tcp.last_end =
		    segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);

		write_unlock_bh(&tcp_lock);
		if (LOG_INVALID(IPPROTO_TCP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				  "nf_ct_tcp: invalid packet ignored ");
		return NF_ACCEPT;
	case TCP_CONNTRACK_MAX:
		/* Invalid packet */
		pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
			 dir, get_conntrack_index(th), old_state);
		write_unlock_bh(&tcp_lock);
		if (LOG_INVALID(IPPROTO_TCP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				  "nf_ct_tcp: invalid state ");
		return -NF_ACCEPT;
	case TCP_CONNTRACK_CLOSE:
		if (index == TCP_RST_SET
		    && ((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
			 && ct->proto.tcp.last_index == TCP_SYN_SET)
			|| (!test_bit(IPS_ASSURED_BIT, &ct->status)
			    && ct->proto.tcp.last_index == TCP_ACK_SET))
		    && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
			/* RST sent to invalid SYN or ACK we had let through
			 * at a) and c) above:
			 *
			 * a) SYN was in window then
			 * c) we hold a half-open connection.
			 *
			 * Delete our connection entry.
			 * We skip window checking, because packet might ACK
			 * segments we ignored. */
			goto in_window;
		}
		/* Just fall through */
	default:
		/* Keep compilers happy. */
		break;
	}

	if (!tcp_in_window(ct, &ct->proto.tcp, dir, index,
			   skb, dataoff, th, pf)) {
		write_unlock_bh(&tcp_lock);
		return -NF_ACCEPT;
	}
     in_window:
	/* From now on we have got in-window packets */
	ct->proto.tcp.last_index = index;
	ct->proto.tcp.last_dir = dir;

	pr_debug("tcp_conntracks: ");
	NF_CT_DUMP_TUPLE(tuple);
	pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
		 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
		 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
		 old_state, new_state);

	ct->proto.tcp.state = new_state;
	if (old_state != new_state
	    && new_state == TCP_CONNTRACK_FIN_WAIT)
		ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
	timeout = ct->proto.tcp.retrans >= nf_ct_tcp_max_retrans
		  && tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans
		  ? nf_ct_tcp_timeout_max_retrans : tcp_timeouts[new_state];
	write_unlock_bh(&tcp_lock);

	nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
	if (new_state != old_state)
		nf_conntrack_event_cache(IPCT_PROTOINFO, skb);

	if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
		/* If only reply is a RST, we can consider ourselves not to
		   have an established connection: this is a fairly common
		   problem case, so we can delete the conntrack
		   immediately.  --RR */
		if (th->rst) {
			if (del_timer(&ct->timeout))
				ct->timeout.function((unsigned long)ct);
			return NF_ACCEPT;
		}
	} else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
		   && (old_state == TCP_CONNTRACK_SYN_RECV
		       || old_state == TCP_CONNTRACK_ESTABLISHED)
		   && new_state == TCP_CONNTRACK_ESTABLISHED) {
		/* Set ASSURED if we see see valid ack in ESTABLISHED
		   after SYN_RECV or a valid answer for a picked up
		   connection. */
		set_bit(IPS_ASSURED_BIT, &ct->status);
		nf_conntrack_event_cache(IPCT_STATUS, skb);
	}
	nf_ct_refresh_acct(ct, ctinfo, skb, timeout);

	return NF_ACCEPT;
}
static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
		     struct tcphdr *tcph, __u32 *sack)
{
	unsigned char buff[(15 * 4) - sizeof(struct tcphdr)];
	unsigned char *ptr;
	int length = (tcph->doff*4) - sizeof(struct tcphdr);
	__u32 tmp;

	if (!length)
		return;

	ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr),
				 length, buff);
	BUG_ON(ptr == NULL);

	/* Fast path for timestamp-only option */
	if (length == TCPOLEN_TSTAMP_ALIGNED*4
	    && *(__be32 *)ptr ==
		__constant_htonl((TCPOPT_NOP << 24)
				 | (TCPOPT_NOP << 16)
				 | (TCPOPT_TIMESTAMP << 8)
				 | TCPOLEN_TIMESTAMP))
		return;

	while (length > 0) {
		int opcode = *ptr++;
		int opsize, i;

		switch (opcode) {
		case TCPOPT_EOL:
			return;
		case TCPOPT_NOP:	/* Ref: RFC 793 section 3.1 */
			length--;
			continue;
		default:
			opsize = *ptr++;
			if (opsize < 2) /* "silly options" */
				return;
			if (opsize > length)
				break;	/* don't parse partial options */

			if (opcode == TCPOPT_SACK
			    && opsize >= (TCPOLEN_SACK_BASE
					  + TCPOLEN_SACK_PERBLOCK)
			    && !((opsize - TCPOLEN_SACK_BASE)
				 % TCPOLEN_SACK_PERBLOCK)) {
				for (i = 0;
				     i < (opsize - TCPOLEN_SACK_BASE);
				     i += TCPOLEN_SACK_PERBLOCK) {
					tmp = ntohl(*((__be32 *)(ptr+i)+1));

					if (after(tmp, *sack))
						*sack = tmp;
				}
				return;
			}
			ptr += opsize - 2;
			length -= opsize;
		}
	}
}
Exemplo n.º 22
0
static int help(struct sk_buff *skb, unsigned int protoff,
		struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
	unsigned int dataoff;
	const struct iphdr *iph;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	const char *data_limit;
	char *data, *ib_ptr;
	int dir = CTINFO2DIR(ctinfo);
	struct nf_conntrack_expect *exp;
	struct nf_conntrack_tuple *tuple;
	__be32 dcc_ip;
	u_int16_t dcc_port;
	__be16 port;
	int i, ret = NF_ACCEPT;
	char *addr_beg_p, *addr_end_p;
	typeof(nf_nat_irc_hook) nf_nat_irc;

	
	if (dir == IP_CT_DIR_REPLY)
		return NF_ACCEPT;

	
	if (ctinfo != IP_CT_ESTABLISHED && ctinfo != IP_CT_ESTABLISHED_REPLY)
		return NF_ACCEPT;

	
	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
	if (th == NULL)
		return NF_ACCEPT;

	
	dataoff = protoff + th->doff*4;
	if (dataoff >= skb->len)
		return NF_ACCEPT;

	spin_lock_bh(&irc_buffer_lock);
	ib_ptr = skb_header_pointer(skb, dataoff, skb->len - dataoff,
				    irc_buffer);
	BUG_ON(ib_ptr == NULL);

	data = ib_ptr;
	data_limit = ib_ptr + skb->len - dataoff;

	while (data < data_limit - (19 + MINMATCHLEN)) {
		if (memcmp(data, "\1DCC ", 5)) {
			data++;
			continue;
		}
		data += 5;
		

		iph = ip_hdr(skb);
		pr_debug("DCC found in master %pI4:%u %pI4:%u\n",
			 &iph->saddr, ntohs(th->source),
			 &iph->daddr, ntohs(th->dest));

		for (i = 0; i < ARRAY_SIZE(dccprotos); i++) {
			if (memcmp(data, dccprotos[i], strlen(dccprotos[i]))) {
				
				continue;
			}
			data += strlen(dccprotos[i]);
			pr_debug("DCC %s detected\n", dccprotos[i]);

			if (parse_dcc(data, data_limit, &dcc_ip,
				       &dcc_port, &addr_beg_p, &addr_end_p)) {
				pr_debug("unable to parse dcc command\n");
				continue;
			}

			pr_debug("DCC bound ip/port: %pI4:%u\n",
				 &dcc_ip, dcc_port);

			
			tuple = &ct->tuplehash[dir].tuple;
			if (tuple->src.u3.ip != dcc_ip &&
			    tuple->dst.u3.ip != dcc_ip) {
				if (net_ratelimit())
					printk(KERN_WARNING
						"Forged DCC command from %pI4: %pI4:%u\n",
						&tuple->src.u3.ip,
						&dcc_ip, dcc_port);
				continue;
			}

			exp = nf_ct_expect_alloc(ct);
			if (exp == NULL) {
				ret = NF_DROP;
				goto out;
			}
			tuple = &ct->tuplehash[!dir].tuple;
			port = htons(dcc_port);
			nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
					  tuple->src.l3num,
					  NULL, &tuple->dst.u3,
					  IPPROTO_TCP, NULL, &port);

			nf_nat_irc = rcu_dereference(nf_nat_irc_hook);
			if (nf_nat_irc && ct->status & IPS_NAT_MASK)
				ret = nf_nat_irc(skb, ctinfo,
						 addr_beg_p - ib_ptr,
						 addr_end_p - addr_beg_p,
						 exp);
			else if (nf_ct_expect_related(exp) != 0)
				ret = NF_DROP;
			nf_ct_expect_put(exp);
			goto out;
		}
	}
 out:
	spin_unlock_bh(&irc_buffer_lock);
	return ret;
}
Exemplo n.º 23
0
static int help(struct sk_buff *skb,
		unsigned int protoff,
		struct nf_conn *ct,
		enum ip_conntrack_info ctinfo)
{
	unsigned int dataoff, datalen;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	void *sb_ptr;
	int ret = NF_ACCEPT;
	int dir = CTINFO2DIR(ctinfo);
	struct nf_ct_sane_master *ct_sane_info;
	struct nf_conntrack_expect *exp;
	struct nf_conntrack_tuple *tuple;
	struct sane_request *req;
	struct sane_reply_net_start *reply;

	ct_sane_info = &nfct_help(ct)->help.ct_sane_info;
	
	if (ctinfo != IP_CT_ESTABLISHED &&
	    ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY)
		return NF_ACCEPT;

	
	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
	if (th == NULL)
		return NF_ACCEPT;

	
	dataoff = protoff + th->doff * 4;
	if (dataoff >= skb->len)
		return NF_ACCEPT;

	datalen = skb->len - dataoff;

	spin_lock_bh(&nf_sane_lock);
	sb_ptr = skb_header_pointer(skb, dataoff, datalen, sane_buffer);
	BUG_ON(sb_ptr == NULL);

	if (dir == IP_CT_DIR_ORIGINAL) {
		if (datalen != sizeof(struct sane_request))
			goto out;

		req = sb_ptr;
		if (req->RPC_code != htonl(SANE_NET_START)) {
			
			ct_sane_info->state = SANE_STATE_NORMAL;
			goto out;
		}

		
		ct_sane_info->state = SANE_STATE_START_REQUESTED;
		goto out;
	}

	
	if (ct_sane_info->state != SANE_STATE_START_REQUESTED)
		goto out;

	
	ct_sane_info->state = SANE_STATE_NORMAL;

	if (datalen < sizeof(struct sane_reply_net_start)) {
		pr_debug("nf_ct_sane: NET_START reply too short\n");
		goto out;
	}

	reply = sb_ptr;
	if (reply->status != htonl(SANE_STATUS_SUCCESS)) {
		
		pr_debug("nf_ct_sane: unsuccessful SANE_STATUS = %u\n",
			 ntohl(reply->status));
		goto out;
	}

	
	if (reply->zero != 0)
		goto out;

	exp = nf_ct_expect_alloc(ct);
	if (exp == NULL) {
		ret = NF_DROP;
		goto out;
	}

	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
			  &tuple->src.u3, &tuple->dst.u3,
			  IPPROTO_TCP, NULL, &reply->port);

	pr_debug("nf_ct_sane: expect: ");
	nf_ct_dump_tuple(&exp->tuple);

	
	if (nf_ct_expect_related(exp) != 0)
		ret = NF_DROP;

	nf_ct_expect_put(exp);

out:
	spin_unlock_bh(&nf_sane_lock);
	return ret;
}
/* Returns verdict for packet, or -1 for invalid. */
static int tcp_packet(struct nf_conn *ct,
		      const struct sk_buff *skb,
		      unsigned int dataoff,
		      enum ip_conntrack_info ctinfo,
		      u_int8_t pf,
		      unsigned int hooknum)
{
	struct net *net = nf_ct_net(ct);
	struct nf_conntrack_tuple *tuple;
	enum tcp_conntrack new_state, old_state;
	enum ip_conntrack_dir dir;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	unsigned long timeout;
	unsigned int index;

	th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
	BUG_ON(th == NULL);

	spin_lock_bh(&ct->lock);
	old_state = ct->proto.tcp.state;
	dir = CTINFO2DIR(ctinfo);
	index = get_conntrack_index(th);
	new_state = tcp_conntracks[dir][index][old_state];
	tuple = &ct->tuplehash[dir].tuple;

	switch (new_state) {
	case TCP_CONNTRACK_SYN_SENT:
		if (old_state < TCP_CONNTRACK_TIME_WAIT)
			break;
		/* RFC 1122: "When a connection is closed actively,
		 * it MUST linger in TIME-WAIT state for a time 2xMSL
		 * (Maximum Segment Lifetime). However, it MAY accept
		 * a new SYN from the remote TCP to reopen the connection
		 * directly from TIME-WAIT state, if..."
		 * We ignore the conditions because we are in the
		 * TIME-WAIT state anyway.
		 *
		 * Handle aborted connections: we and the server
		 * think there is an existing connection but the client
		 * aborts it and starts a new one.
		 */
		if (((ct->proto.tcp.seen[dir].flags
		      | ct->proto.tcp.seen[!dir].flags)
		     & IP_CT_TCP_FLAG_CLOSE_INIT)
		    || (ct->proto.tcp.last_dir == dir
		        && ct->proto.tcp.last_index == TCP_RST_SET)) {
			/* Attempt to reopen a closed/aborted connection.
			 * Delete this connection and look up again. */
			spin_unlock_bh(&ct->lock);

			/* Only repeat if we can actually remove the timer.
			 * Destruction may already be in progress in process
			 * context and we must give it a chance to terminate.
			 */
			if (nf_ct_kill(ct))
				return -NF_REPEAT;
			return NF_DROP;
		}
		/* Fall through */
	case TCP_CONNTRACK_IGNORE:
		/* Ignored packets:
		 *
		 * Our connection entry may be out of sync, so ignore
		 * packets which may signal the real connection between
		 * the client and the server.
		 *
		 * a) SYN in ORIGINAL
		 * b) SYN/ACK in REPLY
		 * c) ACK in reply direction after initial SYN in original.
		 *
		 * If the ignored packet is invalid, the receiver will send
		 * a RST we'll catch below.
		 */
		if (index == TCP_SYNACK_SET
		    && ct->proto.tcp.last_index == TCP_SYN_SET
		    && ct->proto.tcp.last_dir != dir
		    && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
			/* b) This SYN/ACK acknowledges a SYN that we earlier
			 * ignored as invalid. This means that the client and
			 * the server are both in sync, while the firewall is
			 * not. We get in sync from the previously annotated
			 * values.
			 */
			old_state = TCP_CONNTRACK_SYN_SENT;
			new_state = TCP_CONNTRACK_SYN_RECV;
			ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end =
				ct->proto.tcp.last_end;
			ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend =
				ct->proto.tcp.last_end;
			ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin =
				ct->proto.tcp.last_win == 0 ?
					1 : ct->proto.tcp.last_win;
			ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale =
				ct->proto.tcp.last_wscale;
			ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
				ct->proto.tcp.last_flags;
			memset(&ct->proto.tcp.seen[dir], 0,
			       sizeof(struct ip_ct_tcp_state));
			break;
		}
		ct->proto.tcp.last_index = index;
		ct->proto.tcp.last_dir = dir;
		ct->proto.tcp.last_seq = ntohl(th->seq);
		ct->proto.tcp.last_end =
		    segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th);
		ct->proto.tcp.last_win = ntohs(th->window);

		/* a) This is a SYN in ORIGINAL. The client and the server
		 * may be in sync but we are not. In that case, we annotate
		 * the TCP options and let the packet go through. If it is a
		 * valid SYN packet, the server will reply with a SYN/ACK, and
		 * then we'll get in sync. Otherwise, the server ignores it. */
		if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) {
			struct ip_ct_tcp_state seen = {};

			ct->proto.tcp.last_flags =
			ct->proto.tcp.last_wscale = 0;
			tcp_options(skb, dataoff, th, &seen);
			if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
				ct->proto.tcp.last_flags |=
					IP_CT_TCP_FLAG_WINDOW_SCALE;
				ct->proto.tcp.last_wscale = seen.td_scale;
			}
			if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) {
				ct->proto.tcp.last_flags |=
					IP_CT_TCP_FLAG_SACK_PERM;
			}
		}
		spin_unlock_bh(&ct->lock);
		if (LOG_INVALID(net, IPPROTO_TCP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				  "nf_ct_tcp: invalid packet ignored ");
		return NF_ACCEPT;
	case TCP_CONNTRACK_MAX:
		/* Invalid packet */
		pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
			 dir, get_conntrack_index(th), old_state);
		spin_unlock_bh(&ct->lock);
		if (LOG_INVALID(net, IPPROTO_TCP))
			nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
				  "nf_ct_tcp: invalid state ");
		return -NF_ACCEPT;
	case TCP_CONNTRACK_CLOSE:
		if (index == TCP_RST_SET
		    && (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET)
		    && before(ntohl(th->seq), ct->proto.tcp.seen[!dir].td_maxack)) {
			/* Invalid RST  */
			spin_unlock_bh(&ct->lock);
			if (LOG_INVALID(net, IPPROTO_TCP))
				nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
					  "nf_ct_tcp: invalid RST ");
			return -NF_ACCEPT;
		}
		if (index == TCP_RST_SET
		    && ((test_bit(IPS_SEEN_REPLY_BIT, &ct->status)
			 && ct->proto.tcp.last_index == TCP_SYN_SET)
			|| (!test_bit(IPS_ASSURED_BIT, &ct->status)
			    && ct->proto.tcp.last_index == TCP_ACK_SET))
		    && ntohl(th->ack_seq) == ct->proto.tcp.last_end) {
			/* RST sent to invalid SYN or ACK we had let through
			 * at a) and c) above:
			 *
			 * a) SYN was in window then
			 * c) we hold a half-open connection.
			 *
			 * Delete our connection entry.
			 * We skip window checking, because packet might ACK
			 * segments we ignored. */
			goto in_window;
		}
		/* Just fall through */
	default:
		/* Keep compilers happy. */
		break;
	}

	if (!tcp_in_window(ct, &ct->proto.tcp, dir, index,
			   skb, dataoff, th, pf)) {
		spin_unlock_bh(&ct->lock);
		return -NF_ACCEPT;
	}
     in_window:
	/* From now on we have got in-window packets */
	ct->proto.tcp.last_index = index;
	ct->proto.tcp.last_dir = dir;

	pr_debug("tcp_conntracks: ");
	nf_ct_dump_tuple(tuple);
	pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
		 (th->syn ? 1 : 0), (th->ack ? 1 : 0),
		 (th->fin ? 1 : 0), (th->rst ? 1 : 0),
		 old_state, new_state);

	ct->proto.tcp.state = new_state;
	if (old_state != new_state
	    && new_state == TCP_CONNTRACK_FIN_WAIT)
		ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT;

	if (ct->proto.tcp.retrans >= nf_ct_tcp_max_retrans &&
	    tcp_timeouts[new_state] > nf_ct_tcp_timeout_max_retrans)
		timeout = nf_ct_tcp_timeout_max_retrans;
	else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) &
		 IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
		 tcp_timeouts[new_state] > nf_ct_tcp_timeout_unacknowledged)
		timeout = nf_ct_tcp_timeout_unacknowledged;
	else
		timeout = tcp_timeouts[new_state];
	spin_unlock_bh(&ct->lock);

	if (new_state != old_state)
		nf_conntrack_event_cache(IPCT_PROTOINFO, ct);

	if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
		/* If only reply is a RST, we can consider ourselves not to
		   have an established connection: this is a fairly common
		   problem case, so we can delete the conntrack
		   immediately.  --RR */
		if (th->rst) {
			nf_ct_kill_acct(ct, ctinfo, skb);
			return NF_ACCEPT;
		}
	} else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
		   && (old_state == TCP_CONNTRACK_SYN_RECV
		       || old_state == TCP_CONNTRACK_ESTABLISHED)
		   && new_state == TCP_CONNTRACK_ESTABLISHED) {
		/* Set ASSURED if we see see valid ack in ESTABLISHED
		   after SYN_RECV or a valid answer for a picked up
		   connection. */
		set_bit(IPS_ASSURED_BIT, &ct->status);
		nf_conntrack_event_cache(IPCT_ASSURED, ct);
	}
	nf_ct_refresh_acct(ct, ctinfo, skb, timeout);

	return NF_ACCEPT;
}
Exemplo n.º 25
0
static bool
match(const struct sk_buff *skb,
      const struct net_device *in,
      const struct net_device *out,
      const struct xt_match *match,
      const void *matchinfo,
      int offset,
      unsigned int protoff,
      bool *hotdrop)
{
	struct ipv6_rt_hdr _route;
	const struct ipv6_rt_hdr *rh;
	const struct ip6t_rt *rtinfo = matchinfo;
	unsigned int temp;
	unsigned int ptr;
	unsigned int hdrlen = 0;
	bool ret = false;
	struct in6_addr _addr;
	const struct in6_addr *ap;
	int err;

	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, NULL);
	if (err < 0) {
		if (err != -ENOENT)
			*hotdrop = true;
		return false;
	}

	rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route);
	if (rh == NULL) {
		*hotdrop = true;
		return false;
	}

	hdrlen = ipv6_optlen(rh);
	if (skb->len - ptr < hdrlen) {
		/* Pcket smaller than its length field */
		return false;
	}

	DEBUGP("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen);
	DEBUGP("TYPE %04X ", rh->type);
	DEBUGP("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left);

	DEBUGP("IPv6 RT segsleft %02X ",
	       (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
			       rh->segments_left,
			       !!(rtinfo->invflags & IP6T_RT_INV_SGS))));
	DEBUGP("type %02X %02X %02X ",
	       rtinfo->rt_type, rh->type,
	       (!(rtinfo->flags & IP6T_RT_TYP) ||
		((rtinfo->rt_type == rh->type) ^
		 !!(rtinfo->invflags & IP6T_RT_INV_TYP))));
	DEBUGP("len %02X %04X %02X ",
	       rtinfo->hdrlen, hdrlen,
	       (!(rtinfo->flags & IP6T_RT_LEN) ||
		((rtinfo->hdrlen == hdrlen) ^
		 !!(rtinfo->invflags & IP6T_RT_INV_LEN))));
	DEBUGP("res %02X %02X %02X ",
	       (rtinfo->flags & IP6T_RT_RES),
	       ((const struct rt0_hdr *)rh)->reserved,
	       !((rtinfo->flags & IP6T_RT_RES) &&
		 (((const struct rt0_hdr *)rh)->reserved)));

	ret = (rh != NULL)
	      &&
	      (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
			      rh->segments_left,
			      !!(rtinfo->invflags & IP6T_RT_INV_SGS)))
	      &&
	      (!(rtinfo->flags & IP6T_RT_LEN) ||
	       ((rtinfo->hdrlen == hdrlen) ^
		!!(rtinfo->invflags & IP6T_RT_INV_LEN)))
	      &&
	      (!(rtinfo->flags & IP6T_RT_TYP) ||
	       ((rtinfo->rt_type == rh->type) ^
		!!(rtinfo->invflags & IP6T_RT_INV_TYP)));

	if (ret && (rtinfo->flags & IP6T_RT_RES)) {
		const u_int32_t *rp;
		u_int32_t _reserved;
		rp = skb_header_pointer(skb,
					ptr + offsetof(struct rt0_hdr,
						       reserved),
					sizeof(_reserved),
					&_reserved);

		ret = (*rp == 0);
	}

	DEBUGP("#%d ", rtinfo->addrnr);
	if (!(rtinfo->flags & IP6T_RT_FST)) {
		return ret;
	} else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) {
		DEBUGP("Not strict ");
		if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
			DEBUGP("There isn't enough space\n");
			return false;
		} else {
			unsigned int i = 0;

			DEBUGP("#%d ", rtinfo->addrnr);
			for (temp = 0;
			     temp < (unsigned int)((hdrlen - 8) / 16);
			     temp++) {
				ap = skb_header_pointer(skb,
							ptr
							+ sizeof(struct rt0_hdr)
							+ temp * sizeof(_addr),
							sizeof(_addr),
							&_addr);

				BUG_ON(ap == NULL);

				if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {
					DEBUGP("i=%d temp=%d;\n", i, temp);
					i++;
				}
				if (i == rtinfo->addrnr)
					break;
			}
			DEBUGP("i=%d #%d\n", i, rtinfo->addrnr);
			if (i == rtinfo->addrnr)
				return ret;
			else
				return false;
		}
	} else {
		DEBUGP("Strict ");
		if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
			DEBUGP("There isn't enough space\n");
			return false;
		} else {
			DEBUGP("#%d ", rtinfo->addrnr);
			for (temp = 0; temp < rtinfo->addrnr; temp++) {
				ap = skb_header_pointer(skb,
							ptr
							+ sizeof(struct rt0_hdr)
							+ temp * sizeof(_addr),
							sizeof(_addr),
							&_addr);
				BUG_ON(ap == NULL);

				if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp]))
					break;
			}
			DEBUGP("temp=%d #%d\n", temp, rtinfo->addrnr);
			if ((temp == rtinfo->addrnr) &&
			    (temp == (unsigned int)((hdrlen - 8) / 16)))
				return ret;
			else
				return false;
		}
	}

	return false;
}
Exemplo n.º 26
0
static int ebt_filter_arp(const struct sk_buff *skb, const struct net_device *in,
   const struct net_device *out, const void *data, unsigned int datalen)
{
	const struct ebt_arp_info *info = data;
	const struct arphdr *ah;
	struct arphdr _arph;

	ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
	if (ah == NULL)
		return EBT_NOMATCH;
	if (info->bitmask & EBT_ARP_OPCODE && FWINV(info->opcode !=
	   ah->ar_op, EBT_ARP_OPCODE))
		return EBT_NOMATCH;
	if (info->bitmask & EBT_ARP_HTYPE && FWINV(info->htype !=
	   ah->ar_hrd, EBT_ARP_HTYPE))
		return EBT_NOMATCH;
	if (info->bitmask & EBT_ARP_PTYPE && FWINV(info->ptype !=
	   ah->ar_pro, EBT_ARP_PTYPE))
		return EBT_NOMATCH;

	if (info->bitmask & (EBT_ARP_SRC_IP | EBT_ARP_DST_IP | EBT_ARP_GRAT)) {
		const __be32 *sap, *dap;
		__be32 saddr, daddr;

		if (ah->ar_pln != sizeof(__be32) || ah->ar_pro != htons(ETH_P_IP))
			return EBT_NOMATCH;
		sap = skb_header_pointer(skb, sizeof(struct arphdr) +
					ah->ar_hln, sizeof(saddr),
					&saddr);
		if (sap == NULL)
			return EBT_NOMATCH;
		dap = skb_header_pointer(skb, sizeof(struct arphdr) +
					2*ah->ar_hln+sizeof(saddr),
					sizeof(daddr), &daddr);
		if (dap == NULL)
			return EBT_NOMATCH;
		if (info->bitmask & EBT_ARP_SRC_IP &&
		    FWINV(info->saddr != (*sap & info->smsk), EBT_ARP_SRC_IP))
			return EBT_NOMATCH;
		if (info->bitmask & EBT_ARP_DST_IP &&
		    FWINV(info->daddr != (*dap & info->dmsk), EBT_ARP_DST_IP))
			return EBT_NOMATCH;
		if (info->bitmask & EBT_ARP_GRAT &&
		    FWINV(*dap != *sap, EBT_ARP_GRAT))
			return EBT_NOMATCH;
	}

	if (info->bitmask & (EBT_ARP_SRC_MAC | EBT_ARP_DST_MAC)) {
		const unsigned char *mp;
		unsigned char _mac[ETH_ALEN];
		uint8_t verdict, i;

		if (ah->ar_hln != ETH_ALEN || ah->ar_hrd != htons(ARPHRD_ETHER))
			return EBT_NOMATCH;
		if (info->bitmask & EBT_ARP_SRC_MAC) {
			mp = skb_header_pointer(skb, sizeof(struct arphdr),
						sizeof(_mac), &_mac);
			if (mp == NULL)
				return EBT_NOMATCH;
			verdict = 0;
			for (i = 0; i < 6; i++)
				verdict |= (mp[i] ^ info->smaddr[i]) &
				       info->smmsk[i];
			if (FWINV(verdict != 0, EBT_ARP_SRC_MAC))
				return EBT_NOMATCH;
		}

		if (info->bitmask & EBT_ARP_DST_MAC) {
			mp = skb_header_pointer(skb, sizeof(struct arphdr) +
						ah->ar_hln + ah->ar_pln,
						sizeof(_mac), &_mac);
			if (mp == NULL)
				return EBT_NOMATCH;
			verdict = 0;
			for (i = 0; i < 6; i++)
				verdict |= (mp[i] ^ info->dmaddr[i]) &
					info->dmmsk[i];
			if (FWINV(verdict != 0, EBT_ARP_DST_MAC))
				return EBT_NOMATCH;
		}
	}

	return EBT_MATCH;
}
Exemplo n.º 27
0
int
ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
		  struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
{
	struct rt6_info *rt;		/* Route to the other host */
	int local, rc;

	EnterFunction(10);

	rcu_read_lock();
	/* check if it is a connection of no-client-port */
	if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT && !ipvsh->fragoffs)) {
		__be16 _pt, *p;
		p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
		if (p == NULL)
			goto tx_error;
		ip_vs_conn_fill_cport(cp, *p);
		IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
	}

	local = __ip_vs_get_out_rt_v6(cp->af, skb, cp->dest, &cp->daddr.in6,
				      NULL, ipvsh, 0,
				      IP_VS_RT_MODE_LOCAL |
				      IP_VS_RT_MODE_NON_LOCAL |
				      IP_VS_RT_MODE_RDR);
	if (local < 0)
		goto tx_error;
	rt = (struct rt6_info *) skb_dst(skb);
	/*
	 * Avoid duplicate tuple in reply direction for NAT traffic
	 * to local address when connection is sync-ed
	 */
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
	if (cp->flags & IP_VS_CONN_F_SYNC && local) {
		enum ip_conntrack_info ctinfo;
		struct nf_conn *ct = nf_ct_get(skb, &ctinfo);

		if (ct && !nf_ct_is_untracked(ct)) {
			IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, 0,
					 "ip_vs_nat_xmit_v6(): "
					 "stopping DNAT to local address");
			goto tx_error;
		}
	}
#endif

	/* From world but DNAT to loopback address? */
	if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
	    ipv6_addr_type(&cp->daddr.in6) & IPV6_ADDR_LOOPBACK) {
		IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, 0,
				 "ip_vs_nat_xmit_v6(): "
				 "stopping DNAT to loopback address");
		goto tx_error;
	}

	/* copy-on-write the packet before mangling it */
	if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
		goto tx_error;

	if (skb_cow(skb, rt->dst.dev->hard_header_len))
		goto tx_error;

	/* mangle the packet */
	if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
		goto tx_error;
	ipv6_hdr(skb)->daddr = cp->daddr.in6;

	IP_VS_DBG_PKT(10, AF_INET6, pp, skb, 0, "After DNAT");

	/* FIXME: when application helper enlarges the packet and the length
	   is larger than the MTU of outgoing device, there will be still
	   MTU problem. */

	/* Another hack: avoid icmp_send in ip_fragment */
	skb->ignore_df = 1;

	rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
	rcu_read_unlock();

	LeaveFunction(10);
	return rc;

tx_error:
	LeaveFunction(10);
	kfree_skb(skb);
	rcu_read_unlock();
	return NF_STOLEN;
}
Exemplo n.º 28
0
/* We must handle non-linear skbs */
static bool
get_port(const struct sk_buff *skb, int protocol, unsigned int protooff,
	 bool src, __be16 *port, u8 *proto)
{
	switch (protocol) {
	case IPPROTO_TCP: {
		struct tcphdr _tcph;
		const struct tcphdr *th;

		th = skb_header_pointer(skb, protooff, sizeof(_tcph), &_tcph);
		if (th == NULL)
			/* No choice either */
			return false;

		*port = src ? th->source : th->dest;
		break;
	}
	case IPPROTO_SCTP: {
		sctp_sctphdr_t _sh;
		const sctp_sctphdr_t *sh;

		sh = skb_header_pointer(skb, protooff, sizeof(_sh), &_sh);
		if (sh == NULL)
			/* No choice either */
			return false;

		*port = src ? sh->source : sh->dest;
		break;
	}
	case IPPROTO_UDP:
	case IPPROTO_UDPLITE: {
		struct udphdr _udph;
		const struct udphdr *uh;

		uh = skb_header_pointer(skb, protooff, sizeof(_udph), &_udph);
		if (uh == NULL)
			/* No choice either */
			return false;

		*port = src ? uh->source : uh->dest;
		break;
	}
	case IPPROTO_ICMP: {
		struct icmphdr _ich;
		const struct icmphdr *ic;

		ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich);
		if (ic == NULL)
			return false;

		*port = (__force __be16)htons((ic->type << 8) | ic->code);
		break;
	}
	case IPPROTO_ICMPV6: {
		struct icmp6hdr _ich;
		const struct icmp6hdr *ic;

		ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich);
		if (ic == NULL)
			return false;

		*port = (__force __be16)
			htons((ic->icmp6_type << 8) | ic->icmp6_code);
		break;
	}
	default:
		break;
	}
	*proto = protocol;

	return true;
}
Exemplo n.º 29
0
/**
 * ipv6_skb_to_auditdata : fill auditdata from skb
 * @skb : the skb
 * @ad : the audit data to fill
 * @proto : the layer 4 protocol
 *
 * return  0 on success
 */
int ipv6_skb_to_auditdata(struct sk_buff *skb,
		struct common_audit_data *ad, u8 *proto)
{
	int offset, ret = 0;
	struct ipv6hdr *ip6;
	u8 nexthdr;
	__be16 frag_off;

	ip6 = ipv6_hdr(skb);
	if (ip6 == NULL)
		return -EINVAL;
	ad->u.net->v6info.saddr = ip6->saddr;
	ad->u.net->v6info.daddr = ip6->daddr;
	ret = 0;
	/* IPv6 can have several extension header before the Transport header
	 * skip them */
	offset = skb_network_offset(skb);
	offset += sizeof(*ip6);
	nexthdr = ip6->nexthdr;
	offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
	if (offset < 0)
		return 0;
	if (proto)
		*proto = nexthdr;
	switch (nexthdr) {
	case IPPROTO_TCP: {
		struct tcphdr _tcph, *th;

		th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
		if (th == NULL)
			break;

		ad->u.net->sport = th->source;
		ad->u.net->dport = th->dest;
		break;
	}
	case IPPROTO_UDP: {
		struct udphdr _udph, *uh;

		uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
		if (uh == NULL)
			break;

		ad->u.net->sport = uh->source;
		ad->u.net->dport = uh->dest;
		break;
	}
	case IPPROTO_DCCP: {
		struct dccp_hdr _dccph, *dh;

		dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
		if (dh == NULL)
			break;

		ad->u.net->sport = dh->dccph_sport;
		ad->u.net->dport = dh->dccph_dport;
		break;
	}
	case IPPROTO_SCTP: {
		struct sctphdr _sctph, *sh;

		sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
		if (sh == NULL)
			break;
		ad->u.net->sport = sh->source;
		ad->u.net->dport = sh->dest;
		break;
	}
	default:
		ret = -EINVAL;
	}
	return ret;
}
Exemplo n.º 30
0
static int
tcp_conn_schedule(struct netns_ipvs *ipvs, int af, struct sk_buff *skb,
		  struct ip_vs_proto_data *pd,
		  int *verdict, struct ip_vs_conn **cpp,
		  struct ip_vs_iphdr *iph)
{
	struct ip_vs_service *svc;
	struct tcphdr _tcph, *th;
	__be16 _ports[2], *ports = NULL;

	/* In the event of icmp, we're only guaranteed to have the first 8
	 * bytes of the transport header, so we only check the rest of the
	 * TCP packet for non-ICMP packets
	 */
	if (likely(!ip_vs_iph_icmp(iph))) {
		th = skb_header_pointer(skb, iph->len, sizeof(_tcph), &_tcph);
		if (th) {
			if (th->rst || !(sysctl_sloppy_tcp(ipvs) || th->syn))
				return 1;
			ports = &th->source;
		}
	} else {
		ports = skb_header_pointer(
			skb, iph->len, sizeof(_ports), &_ports);
	}

	if (!ports) {
		*verdict = NF_DROP;
		return 0;
	}

	/* No !th->ack check to allow scheduling on SYN+ACK for Active FTP */
	rcu_read_lock();

	if (likely(!ip_vs_iph_inverse(iph)))
		svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol,
					 &iph->daddr, ports[1]);
	else
		svc = ip_vs_service_find(ipvs, af, skb->mark, iph->protocol,
					 &iph->saddr, ports[0]);

	if (svc) {
		int ignored;

		if (ip_vs_todrop(ipvs)) {
			/*
			 * It seems that we are very loaded.
			 * We have to drop this packet :(
			 */
			rcu_read_unlock();
			*verdict = NF_DROP;
			return 0;
		}

		/*
		 * Let the virtual server select a real server for the
		 * incoming connection, and create a connection entry.
		 */
		*cpp = ip_vs_schedule(svc, skb, pd, &ignored, iph);
		if (!*cpp && ignored <= 0) {
			if (!ignored)
				*verdict = ip_vs_leave(svc, skb, pd, iph);
			else
				*verdict = NF_DROP;
			rcu_read_unlock();
			return 0;
		}
	}
	rcu_read_unlock();
	/* NF_ACCEPT */
	return 1;
}