C++ (Cpp) tcp_error_log Examples

Example #1

File: nf_conntrack_proto_tcp.c Project: AlexShiLucky/linux

/* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c.  */
static bool tcp_error(const struct tcphdr *th,
		      struct sk_buff *skb,
		      unsigned int dataoff,
		      const struct nf_hook_state *state)
{
	unsigned int tcplen = skb->len - dataoff;
	u8 tcpflags;

	/* Not whole TCP header or malformed packet */
	if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
		tcp_error_log(skb, state, "truncated packet");
		return true;
	}

	/* Checksum invalid? Ignore.
	 * We skip checking packets on the outgoing path
	 * because the checksum is assumed to be correct.
	 */
	/* FIXME: Source route IP option packets --RR */
	if (state->net->ct.sysctl_checksum &&
	    state->hook == NF_INET_PRE_ROUTING &&
	    nf_checksum(skb, state->hook, dataoff, IPPROTO_TCP, state->pf)) {
		tcp_error_log(skb, state, "bad checksum");
		return true;
	}

	/* Check TCP flags. */
	tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH));
	if (!tcp_valid_flags[tcpflags]) {
		tcp_error_log(skb, state, "invalid tcp flag combination");
		return true;
	}

	return false;
}

Example #2

File: nf_conntrack_proto_tcp.c Project: ReneNyffenegger/linux

/* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c.  */
static int tcp_error(struct net *net, struct nf_conn *tmpl,
		     struct sk_buff *skb,
		     unsigned int dataoff,
		     u_int8_t pf,
		     unsigned int hooknum)
{
	const struct tcphdr *th;
	struct tcphdr _tcph;
	unsigned int tcplen = skb->len - dataoff;
	u_int8_t tcpflags;

	/* Smaller that minimal TCP header? */
	th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph);
	if (th == NULL) {
		tcp_error_log(skb, net, pf, "short packet");
		return -NF_ACCEPT;
	}

	/* Not whole TCP header or malformed packet */
	if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) {
		tcp_error_log(skb, net, pf, "truncated packet");
		return -NF_ACCEPT;
	}

	/* Checksum invalid? Ignore.
	 * We skip checking packets on the outgoing path
	 * because the checksum is assumed to be correct.
	 */
	/* FIXME: Source route IP option packets --RR */
	if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
	    nf_checksum(skb, hooknum, dataoff, IPPROTO_TCP, pf)) {
		tcp_error_log(skb, net, pf, "bad checksum");
		return -NF_ACCEPT;
	}

	/* Check TCP flags. */
	tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH));
	if (!tcp_valid_flags[tcpflags]) {
		tcp_error_log(skb, net, pf, "invalid tcp flag combination");
		return -NF_ACCEPT;
	}

	return NF_ACCEPT;
}