static BOOTPClient *request_addr(const ipaddr_t *paddr,
const uint8_t *macaddr)
{
uint32_t req_addr = ip_geth(*paddr);
uint32_t spec_addr = special_addr_ip;
BOOTPClient *bc;
if (req_addr >= (spec_addr | START_ADDR) &&
req_addr < (spec_addr | (NB_ADDR + START_ADDR))) {
bc = &bootp_clients[(req_addr & 0xff) - START_ADDR];
if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6)) {
bc->allocated = 1;
return bc;
}
}
return NULL;
}
static void bootp_reply(const struct bootp_t *bp)
{
BOOTPClient *bc = NULL;
struct mbuf *m;
struct bootp_t *rbp;
SockAddress saddr, daddr;
uint32_t dns_addr;
const ipaddr_t *preq_addr;
int dhcp_msg_type, val;
uint8_t *q;
/* extract exact DHCP msg type */
dhcp_decode(bp, &dhcp_msg_type, &preq_addr);
dprintf("bootp packet op=%d msgtype=%d", bp->bp_op, dhcp_msg_type);
if (preq_addr) {
dprintf(" req_addr=%08x\n", ntohl(*(uint32_t*)preq_addr));
} else {
dprintf("\n");
}
if (dhcp_msg_type == 0)
dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
if (dhcp_msg_type != DHCPDISCOVER &&
dhcp_msg_type != DHCPREQUEST)
return;
/* XXX: this is a hack to get the client mac address */
memcpy(client_ethaddr, bp->bp_hwaddr, 6);
if ((m = m_get()) == NULL)
return;
m->m_data += IF_MAXLINKHDR;
rbp = (struct bootp_t *)m->m_data;
m->m_data += sizeof(struct udpiphdr);
memset(rbp, 0, sizeof(struct bootp_t));
if (dhcp_msg_type == DHCPDISCOVER) {
if (preq_addr) {
bc = request_addr(preq_addr, client_ethaddr);
if (bc) {
sock_address_init_inet(&daddr, ip_geth(*preq_addr), BOOTP_CLIENT);
}
}
if (!bc) {
new_addr:
bc = get_new_addr(&daddr, client_ethaddr);
if (!bc) {
dprintf("no address left\n");
return;
}
}
memcpy(bc->macaddr, client_ethaddr, 6);
} else if (preq_addr) {
bc = request_addr(preq_addr, client_ethaddr);
if (bc) {
sock_address_init_inet(&daddr, ip_geth(*preq_addr), BOOTP_CLIENT);
memcpy(bc->macaddr, client_ethaddr, 6);
} else {
sock_address_init_inet(&daddr, 0, BOOTP_CLIENT);
}
} else {
bc = find_addr(&daddr, bp->bp_hwaddr);
if (!bc) {
/* if never assigned, behaves as if it was already
assigned (windows fix because it remembers its address) */
goto new_addr;
}
}
sock_address_init_inet( &saddr, special_addr_ip | CTL_ALIAS,
BOOTP_SERVER );
rbp->bp_op = BOOTP_REPLY;
rbp->bp_xid = bp->bp_xid;
rbp->bp_htype = 1;
rbp->bp_hlen = 6;
memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
rbp->bp_yiaddr = htonl(sock_address_get_ip(&daddr)); /* Client IP address */
rbp->bp_siaddr = htonl(sock_address_get_ip(&saddr)); /* Server IP address */
q = rbp->bp_vend;
memcpy(q, rfc1533_cookie, 4);
q += 4;
if (bc) {
uint32_t saddr_ip = htonl(sock_address_get_ip(&saddr));
dprintf("%s addr=%08x\n",
(dhcp_msg_type == DHCPDISCOVER) ? "offered" : "ack'ed",
sock_address_get_ip(&daddr));
if (dhcp_msg_type == DHCPDISCOVER) {
*q++ = RFC2132_MSG_TYPE;
*q++ = 1;
*q++ = DHCPOFFER;
} else /* DHCPREQUEST */ {
*q++ = RFC2132_MSG_TYPE;
*q++ = 1;
*q++ = DHCPACK;
}
if (bootp_filename)
snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s",
bootp_filename);
*q++ = RFC2132_SRV_ID;
*q++ = 4;
memcpy(q, &saddr_ip, 4);
q += 4;
*q++ = RFC1533_NETMASK;
*q++ = 4;
*q++ = 0xff;
*q++ = 0xff;
*q++ = 0xff;
*q++ = 0x00;
if (!slirp_restrict) {
*q++ = RFC1533_GATEWAY;
*q++ = 4;
memcpy(q, &saddr_ip, 4);
q += 4;
*q++ = RFC1533_DNS;
*q++ = 4;
dns_addr = htonl(special_addr_ip | CTL_DNS);
memcpy(q, &dns_addr, 4);
q += 4;
}
*q++ = RFC2132_LEASE_TIME;
*q++ = 4;
val = htonl(LEASE_TIME);
memcpy(q, &val, 4);
q += 4;
if (*slirp_hostname) {
val = strlen(slirp_hostname);
*q++ = RFC1533_HOSTNAME;
*q++ = val;
memcpy(q, slirp_hostname, val);
q += val;
}
} else {
static const char nak_msg[] = "requested address not available";
dprintf("nak'ed addr=%08x\n", ip_geth(*preq_addr));
*q++ = RFC2132_MSG_TYPE;
*q++ = 1;
*q++ = DHCPNAK;
*q++ = RFC2132_MESSAGE;
*q++ = sizeof(nak_msg) - 1;
memcpy(q, nak_msg, sizeof(nak_msg) - 1);
q += sizeof(nak_msg) - 1;
}
*q++ = RFC1533_END;
sock_address_init_inet(&daddr, 0xffffffffu, BOOTP_CLIENT);
m->m_len = sizeof(struct bootp_t) -
sizeof(struct ip) - sizeof(struct udphdr);
udp_output2_(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
}
void
icmp_input(struct mbuf *m, int hlen)
{
register struct icmp *icp;
register struct ip *ip=mtod(m, struct ip *);
int icmplen=ip->ip_len;
/* int code; */
DEBUG_CALL("icmp_input");
DEBUG_ARG("m = %lx", (long )m);
DEBUG_ARG("m_len = %d", m->m_len);
STAT(icmpstat.icps_received++);
/*
* Locate icmp structure in mbuf, and check
* that its not corrupted and of at least minimum length.
*/
if (icmplen < ICMP_MINLEN) { /* min 8 bytes payload */
STAT(icmpstat.icps_tooshort++);
freeit:
m_freem(m);
goto end_error;
}
m->m_len -= hlen;
m->m_data += hlen;
icp = mtod(m, struct icmp *);
if (cksum(m, icmplen)) {
STAT(icmpstat.icps_checksum++);
goto freeit;
}
m->m_len += hlen;
m->m_data -= hlen;
/* icmpstat.icps_inhist[icp->icmp_type]++; */
/* code = icp->icmp_code; */
DEBUG_ARG("icmp_type = %d", icp->icmp_type);
switch (icp->icmp_type) {
case ICMP_ECHO:
icp->icmp_type = ICMP_ECHOREPLY;
ip->ip_len += hlen; /* since ip_input subtracts this */
if (ip_geth(ip->ip_dst) == alias_addr_ip) {
icmp_reflect(m);
} else {
struct socket *so;
SockAddress addr;
uint32_t addr_ip;
uint16_t addr_port;
if ((so = socreate()) == NULL) goto freeit;
if(udp_attach(so) == -1) {
DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n",
errno,errno_str));
sofree(so);
m_free(m);
goto end_error;
}
so->so_m = m;
so->so_faddr_ip = ip_geth(ip->ip_dst);
so->so_faddr_port = 7;
so->so_laddr_ip = ip_geth(ip->ip_src);
so->so_laddr_port = 9;
so->so_iptos = ip->ip_tos;
so->so_type = IPPROTO_ICMP;
so->so_state = SS_ISFCONNECTED;
/* Send the packet */
if ((so->so_faddr_ip & 0xffffff00) == special_addr_ip) {
/* It's an alias */
int low = so->so_faddr_ip & 0xff;
if (low >= CTL_DNS && low < CTL_DNS + dns_addr_count)
addr_ip = dns_addr[low - CTL_DNS];
else
addr_ip = loopback_addr_ip;
} else {
addr_ip = so->so_faddr_ip;
}
addr_port = so->so_faddr_port;
sock_address_init_inet( &addr, addr_ip, addr_port );
if(socket_sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), &addr) < 0) {
DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
errno,errno_str));
icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,errno_str);
udp_detach(so);
}
} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
break;
case ICMP_UNREACH:
/* XXX? report error? close socket? */
case ICMP_TIMXCEED:
case ICMP_PARAMPROB:
case ICMP_SOURCEQUENCH:
case ICMP_TSTAMP:
case ICMP_MASKREQ:
case ICMP_REDIRECT:
STAT(icmpstat.icps_notsupp++);
m_freem(m);
break;
default:
STAT(icmpstat.icps_badtype++);
m_freem(m);
} /* swith */
end_error:
/* m is m_free()'d xor put in a socket xor or given to ip_send */
return;
}
void
icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
const char *message)
{
unsigned hlen, shlen, s_ip_len;
register struct ip *ip;
register struct icmp *icp;
register struct mbuf *m;
DEBUG_CALL("icmp_error");
DEBUG_ARG("msrc = %lx", (long )msrc);
DEBUG_ARG("msrc_len = %d", msrc->m_len);
if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error;
/* check msrc */
if(!msrc) goto end_error;
ip = mtod(msrc, struct ip *);
#ifdef DEBUG
{ char bufa[20], bufb[20];
strcpy(bufa, inet_iptostr(ip_geth(ip->ip_src)));
strcpy(bufb, inet_iptostr(ip_geth(ip->ip_dst)));
DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
}
#endif
if(ip->ip_off & IP_OFFMASK) goto end_error; /* Only reply to fragment 0 */
shlen=ip->ip_hl << 2;
s_ip_len=ip->ip_len;
if(ip->ip_p == IPPROTO_ICMP) {
icp = (struct icmp *)((char *)ip + shlen);
/*
* Assume any unknown ICMP type is an error. This isn't
* specified by the RFC, but think about it..
*/
if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error;
}
/* make a copy */
if(!(m=m_get())) goto end_error; /* get mbuf */
{ int new_m_size;
new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN;
if(new_m_size>m->m_size) m_inc(m, new_m_size);
}
memcpy(m->m_data, msrc->m_data, msrc->m_len);
m->m_len = msrc->m_len; /* copy msrc to m */
/* make the header of the reply packet */
ip = mtod(m, struct ip *);
hlen= sizeof(struct ip ); /* no options in reply */
/* fill in icmp */
m->m_data += hlen;
m->m_len -= hlen;
icp = mtod(m, struct icmp *);
if(minsize) s_ip_len=shlen+ICMP_MINLEN; /* return header+8b only */
else if(s_ip_len>ICMP_MAXDATALEN) /* maximum size */
s_ip_len=ICMP_MAXDATALEN;
m->m_len=ICMP_MINLEN+s_ip_len; /* 8 bytes ICMP header */
/* min. size = 8+sizeof(struct ip)+8 */
icp->icmp_type = type;
icp->icmp_code = code;
icp->icmp_id = 0;
icp->icmp_seq = 0;
memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
HTONS(icp->icmp_ip.ip_len);
HTONS(icp->icmp_ip.ip_id);
HTONS(icp->icmp_ip.ip_off);
#ifdef DEBUG
if(message) { /* DEBUG : append message to ICMP packet */
int message_len;
char *cpnt;
message_len=strlen(message);
if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN;
cpnt=(char *)m->m_data+m->m_len;
memcpy(cpnt, message, message_len);
m->m_len+=message_len;
}
#endif
icp->icmp_cksum = 0;
icp->icmp_cksum = cksum(m, m->m_len);
m->m_data -= hlen;
m->m_len += hlen;
/* fill in ip */
ip->ip_hl = hlen >> 2;
ip->ip_len = m->m_len;
ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */
ip->ip_ttl = MAXTTL;
ip->ip_p = IPPROTO_ICMP;
ip->ip_dst = ip->ip_src; /* ip adresses */
ip->ip_src = ip_setn(alias_addr_ip);
(void ) ip_output((struct socket *)NULL, m);
STAT(icmpstat.icps_reflect++);
end_error:
return;
}
/*
* TCP input routine, follows pages 65-76 of the
* protocol specification dated September, 1981 very closely.
*/
void
tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
{
struct ip save_ip, *ip;
register struct tcpiphdr *ti;
caddr_t optp = NULL;
int optlen = 0;
int len, tlen, off;
register struct tcpcb *tp = NULL;
register int tiflags;
struct socket *so = NULL;
int todrop, acked, ourfinisacked, needoutput = 0;
/* int dropsocket = 0; */
int iss = 0;
u_long tiwin;
int ret;
/* int ts_present = 0; */
struct ex_list *ex_ptr;
DEBUG_CALL("tcp_input");
DEBUG_ARGS((dfd," m = %8lx iphlen = %2d inso = %lx\n",
(long )m, iphlen, (long )inso ));
/*
* If called with m == 0, then we're continuing the connect
*/
if (m == NULL) {
so = inso;
/* Re-set a few variables */
tp = sototcpcb(so);
m = so->so_m;
so->so_m = NULL;
ti = so->so_ti;
tiwin = ti->ti_win;
tiflags = ti->ti_flags;
goto cont_conn;
}
STAT(tcpstat.tcps_rcvtotal++);
/*
* Get IP and TCP header together in first mbuf.
* Note: IP leaves IP header in first mbuf.
*/
ti = mtod(m, struct tcpiphdr *);
if (iphlen > sizeof(struct ip )) {
ip_stripoptions(m, (struct mbuf *)0);
iphlen=sizeof(struct ip );
}
/* XXX Check if too short */
/*
* Save a copy of the IP header in case we want restore it
* for sending an ICMP error message in response.
*/
ip=mtod(m, struct ip *);
save_ip = *ip;
save_ip.ip_len+= iphlen;
/*
* Checksum extended TCP header and data.
*/
tlen = ((struct ip *)ti)->ip_len;
tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
memset(&ti->ti_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
ti->ti_x1 = 0;
ti->ti_len = htons((u_int16_t)tlen);
len = sizeof(struct ip ) + tlen;
/* keep checksum for ICMP reply
* ti->ti_sum = cksum(m, len);
* if (ti->ti_sum) { */
if(cksum(m, len)) {
STAT(tcpstat.tcps_rcvbadsum++);
goto drop;
}
/*
* Check that TCP offset makes sense,
* pull out TCP options and adjust length. XXX
*/
off = ti->ti_off << 2;
if (off < sizeof (struct tcphdr) || off > tlen) {
STAT(tcpstat.tcps_rcvbadoff++);
goto drop;
}
tlen -= off;
ti->ti_len = tlen;
if (off > sizeof (struct tcphdr)) {
optlen = off - sizeof (struct tcphdr);
optp = mtod(m, caddr_t) + sizeof (struct tcpiphdr);
/*
* Do quick retrieval of timestamp options ("options
* prediction?"). If timestamp is the only option and it's
* formatted as recommended in RFC 1323 appendix A, we
* quickly get the values now and not bother calling
* tcp_dooptions(), etc.
*/
/* if ((optlen == TCPOLEN_TSTAMP_APPA ||
* (optlen > TCPOLEN_TSTAMP_APPA &&
* optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) &&
* *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) &&
* (ti->ti_flags & TH_SYN) == 0) {
* ts_present = 1;
* ts_val = ntohl(*(u_int32_t *)(optp + 4));
* ts_ecr = ntohl(*(u_int32_t *)(optp + 8));
* optp = NULL; / * we've parsed the options * /
* }
*/
}
tiflags = ti->ti_flags;
/*
* Convert TCP protocol specific fields to host format.
*/
NTOHL(ti->ti_seq);
NTOHL(ti->ti_ack);
NTOHS(ti->ti_win);
NTOHS(ti->ti_urp);
/*
* Drop TCP, IP headers and TCP options.
*/
m->m_data += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
m->m_len -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
if (slirp_restrict) {
for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next)
if (ex_ptr->ex_fport == port_geth(ti->ti_dport) &&
(ip_geth(ti->ti_dst) & 0xff) == ex_ptr->ex_addr)
break;
if (!ex_ptr)
goto drop;
}
/*
* Locate pcb for segment.
*/
findso:
so = tcp_last_so;
{
uint32_t srcip = ip_geth(ti->ti_src);
uint32_t dstip = ip_geth(ti->ti_dst);
uint16_t dstport = port_geth(ti->ti_dport);
uint16_t srcport = port_geth(ti->ti_sport);
if (so->so_faddr_port != dstport ||
so->so_laddr_port != srcport ||
so->so_laddr_ip != srcip ||
so->so_faddr_ip != dstip) {
so = solookup(&tcb, srcip, srcport, dstip, dstport);
if (so)
tcp_last_so = so;
STAT(tcpstat.tcps_socachemiss++);
}
}
/*
* If the state is CLOSED (i.e., TCB does not exist) then
* all data in the incoming segment is discarded.
* If the TCB exists but is in CLOSED state, it is embryonic,
* but should either do a listen or a connect soon.
*
* state == CLOSED means we've done socreate() but haven't
* attached it to a protocol yet...
*
* XXX If a TCB does not exist, and the TH_SYN flag is
* the only flag set, then create a session, mark it
* as if it was LISTENING, and continue...
*/
if (so == NULL) {
if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)
goto dropwithreset;
if ((so = socreate()) == NULL)
goto dropwithreset;
if (tcp_attach(so) < 0) {
free(so); /* Not sofree (if it failed, it's not insqued) */
goto dropwithreset;
}
sbreserve(&so->so_snd, TCP_SNDSPACE);
sbreserve(&so->so_rcv, TCP_RCVSPACE);
/* tcp_last_so = so; */ /* XXX ? */
/* tp = sototcpcb(so); */
so->so_laddr_ip = ip_geth(ti->ti_src);
so->so_laddr_port = port_geth(ti->ti_sport);
so->so_faddr_ip = ip_geth(ti->ti_dst);
so->so_faddr_port = port_geth(ti->ti_dport);
if ((so->so_iptos = tcp_tos(so)) == 0)
so->so_iptos = ((struct ip *)ti)->ip_tos;
tp = sototcpcb(so);
tp->t_state = TCPS_LISTEN;
}
/*
* If this is a still-connecting socket, this probably
* a retransmit of the SYN. Whether it's a retransmit SYN
* or something else, we nuke it.
*/
if (so->so_state & SS_ISFCONNECTING)
goto drop;
tp = sototcpcb(so);
/* XXX Should never fail */
if (tp == NULL)
goto dropwithreset;
if (tp->t_state == TCPS_CLOSED)
goto drop;
/* Unscale the window into a 32-bit value. */
/* if ((tiflags & TH_SYN) == 0)
* tiwin = ti->ti_win << tp->snd_scale;
* else
*/
tiwin = ti->ti_win;
/*
* Segment received on connection.
* Reset idle time and keep-alive timer.
*/
tp->t_idle = 0;
if (SO_OPTIONS)
tp->t_timer[TCPT_KEEP] = TCPTV_KEEPINTVL;
else
tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_IDLE;
/*
* Process options if not in LISTEN state,
* else do it below (after getting remote address).
*/
if (optp && tp->t_state != TCPS_LISTEN)
tcp_dooptions(tp, (u_char *)optp, optlen, ti);
/* , */
/* &ts_present, &ts_val, &ts_ecr); */
/*
* Header prediction: check for the two common cases
* of a uni-directional data xfer. If the packet has
* no control flags, is in-sequence, the window didn't
* change and we're not retransmitting, it's a
* candidate. If the length is zero and the ack moved
* forward, we're the sender side of the xfer. Just
* free the data acked & wake any higher level process
* that was blocked waiting for space. If the length
* is non-zero and the ack didn't move, we're the
* receiver side. If we're getting packets in-order
* (the reassembly queue is empty), add the data to
* the socket buffer and note that we need a delayed ack.
*
* XXX Some of these tests are not needed
* eg: the tiwin == tp->snd_wnd prevents many more
* predictions.. with no *real* advantage..
*/
if (tp->t_state == TCPS_ESTABLISHED &&
(tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
/* (!ts_present || TSTMP_GEQ(ts_val, tp->ts_recent)) && */
ti->ti_seq == tp->rcv_nxt &&
tiwin && tiwin == tp->snd_wnd &&
tp->snd_nxt == tp->snd_max) {
/*
* If last ACK falls within this segment's sequence numbers,
* record the timestamp.
*/
/* if (ts_present && SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) &&
* SEQ_LT(tp->last_ack_sent, ti->ti_seq + ti->ti_len)) {
* tp->ts_recent_age = tcp_now;
* tp->ts_recent = ts_val;
* }
*/
if (ti->ti_len == 0) {
if (SEQ_GT(ti->ti_ack, tp->snd_una) &&
SEQ_LEQ(ti->ti_ack, tp->snd_max) &&
tp->snd_cwnd >= tp->snd_wnd) {
/*
* this is a pure ack for outstanding data.
*/
STAT(tcpstat.tcps_predack++);
/* if (ts_present)
* tcp_xmit_timer(tp, tcp_now-ts_ecr+1);
* else
*/ if (tp->t_rtt &&
SEQ_GT(ti->ti_ack, tp->t_rtseq))
tcp_xmit_timer(tp, tp->t_rtt);
acked = ti->ti_ack - tp->snd_una;
STAT(tcpstat.tcps_rcvackpack++);
STAT(tcpstat.tcps_rcvackbyte += acked);
sbdrop(&so->so_snd, acked);
tp->snd_una = ti->ti_ack;
m_freem(m);
/*
* If all outstanding data are acked, stop
* retransmit timer, otherwise restart timer
* using current (possibly backed-off) value.
* If process is waiting for space,
* wakeup/selwakeup/signal. If data
* are ready to send, let tcp_output
* decide between more output or persist.
*/
if (tp->snd_una == tp->snd_max)
tp->t_timer[TCPT_REXMT] = 0;
else if (tp->t_timer[TCPT_PERSIST] == 0)
tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
/*
* There's room in so_snd, sowwakup will read()
* from the socket if we can
*/
/* if (so->so_snd.sb_flags & SB_NOTIFY)
* sowwakeup(so);
*/
/*
* This is called because sowwakeup might have
* put data into so_snd. Since we don't so sowwakeup,
* we don't need this.. XXX???
*/
if (so->so_snd.sb_cc)
(void) tcp_output(tp);
return;
}
} else if (ti->ti_ack == tp->snd_una &&
tcpfrag_list_empty(tp) &&
ti->ti_len <= sbspace(&so->so_rcv)) {
/*
* this is a pure, in-sequence data packet
* with nothing on the reassembly queue and
* we have enough buffer space to take it.
*/
STAT(tcpstat.tcps_preddat++);
tp->rcv_nxt += ti->ti_len;
STAT(tcpstat.tcps_rcvpack++);
STAT(tcpstat.tcps_rcvbyte += ti->ti_len);
/*
* Add data to socket buffer.
*/
if (so->so_emu) {
if (tcp_emu(so,m)) sbappend(so, m);
} else
sbappend(so, m);
/*
* XXX This is called when data arrives. Later, check
* if we can actually write() to the socket
* XXX Need to check? It's be NON_BLOCKING
*/
/* sorwakeup(so); */
/*
* If this is a short packet, then ACK now - with Nagel
* congestion avoidance sender won't send more until
* he gets an ACK.
*
* It is better to not delay acks at all to maximize
* TCP throughput. See RFC 2581.
*/
tp->t_flags |= TF_ACKNOW;
tcp_output(tp);
return;
}
} /* header prediction */
/*
* Calculate amount of space in receive window,
* and then do TCP input processing.
* Receive window is amount of space in rcv queue,
* but not less than advertised window.
*/
{ int win;
win = sbspace(&so->so_rcv);
if (win < 0)
win = 0;
tp->rcv_wnd = max(win, (int)(tp->rcv_adv - tp->rcv_nxt));
}
switch (tp->t_state) {
/*
* If the state is LISTEN then ignore segment if it contains an RST.
* If the segment contains an ACK then it is bad and send a RST.
* If it does not contain a SYN then it is not interesting; drop it.
* Don't bother responding if the destination was a broadcast.
* Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
* tp->iss, and send a segment:
* <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
* Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
* Fill in remote peer address fields if not previously specified.
* Enter SYN_RECEIVED state, and process any other fields of this
* segment in this state.
*/
case TCPS_LISTEN: {
if (tiflags & TH_RST)
goto drop;
if (tiflags & TH_ACK)
goto dropwithreset;
if ((tiflags & TH_SYN) == 0)
goto drop;
/*
* This has way too many gotos...
* But a bit of spaghetti code never hurt anybody :)
*/
/*
* If this is destined for the control address, then flag to
* tcp_ctl once connected, otherwise connect
*/
if ((so->so_faddr_ip & 0xffffff00) == special_addr_ip) {
int lastbyte=so->so_faddr_ip & 0xff;
if (lastbyte!=CTL_ALIAS && lastbyte!=CTL_DNS) {
#if 0
if(lastbyte==CTL_CMD || lastbyte==CTL_EXEC) {
/* Command or exec adress */
so->so_state |= SS_CTL;
} else
#endif
{
/* May be an add exec */
for(ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
if(ex_ptr->ex_fport == so->so_faddr_port &&
lastbyte == ex_ptr->ex_addr) {
so->so_state |= SS_CTL;
break;
}
}
}
if(so->so_state & SS_CTL) goto cont_input;
}
/* CTL_ALIAS: Do nothing, tcp_fconnect will be called on it */
}
if (so->so_emu & EMU_NOCONNECT) {
so->so_emu &= ~EMU_NOCONNECT;
goto cont_input;
}
if((tcp_fconnect(so) == -1) && (errno != EINPROGRESS) &&
(errno != EWOULDBLOCK) && (errno != EAGAIN)) {
u_char code=ICMP_UNREACH_NET;
DEBUG_MISC((dfd," tcp fconnect errno = %d-%s\n",
errno,errno_str));
if(errno == ECONNREFUSED) {
/* ACK the SYN, send RST to refuse the connection */
tcp_respond(tp, ti, m, ti->ti_seq+1, (tcp_seq)0,
TH_RST|TH_ACK);
} else {
if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
HTONL(ti->ti_seq); /* restore tcp header */
HTONL(ti->ti_ack);
HTONS(ti->ti_win);
HTONS(ti->ti_urp);
m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
m->m_len += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
*ip=save_ip;
icmp_error(m, ICMP_UNREACH,code, 0,errno_str);
}
tp = tcp_close(tp);
m_free(m);
} else {
/*
* Haven't connected yet, save the current mbuf
* and ti, and return
* XXX Some OS's don't tell us whether the connect()
* succeeded or not. So we must time it out.
*/
so->so_m = m;
so->so_ti = ti;
tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
tp->t_state = TCPS_SYN_RECEIVED;
}
return;
cont_conn:
/* m==NULL
* Check if the connect succeeded
*/
if (so->so_state & SS_NOFDREF) {
tp = tcp_close(tp);
goto dropwithreset;
}
cont_input:
tcp_template(tp);
if (optp)
tcp_dooptions(tp, (u_char *)optp, optlen, ti);
/* , */
/* &ts_present, &ts_val, &ts_ecr); */
if (iss)
tp->iss = iss;
else
tp->iss = tcp_iss;
tcp_iss += TCP_ISSINCR/2;
tp->irs = ti->ti_seq;
tcp_sendseqinit(tp);
tcp_rcvseqinit(tp);
tp->t_flags |= TF_ACKNOW;
tp->t_state = TCPS_SYN_RECEIVED;
tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
STAT(tcpstat.tcps_accepts++);
goto trimthenstep6;
} /* case TCPS_LISTEN */
/*
* If the state is SYN_SENT:
* if seg contains an ACK, but not for our SYN, drop the input.
* if seg contains a RST, then drop the connection.
* if seg does not contain SYN, then drop it.
* Otherwise this is an acceptable SYN segment
* initialize tp->rcv_nxt and tp->irs
* if seg contains ack then advance tp->snd_una
* if SYN has been acked change to ESTABLISHED else SYN_RCVD state
* arrange for segment to be acked (eventually)
* continue processing rest of data/controls, beginning with URG
*/
case TCPS_SYN_SENT:
if ((tiflags & TH_ACK) &&
(SEQ_LEQ(ti->ti_ack, tp->iss) ||
SEQ_GT(ti->ti_ack, tp->snd_max)))
goto dropwithreset;
if (tiflags & TH_RST) {
if (tiflags & TH_ACK)
tp = tcp_drop(tp,0); /* XXX Check t_softerror! */
goto drop;
}
if ((tiflags & TH_SYN) == 0)
goto drop;
if (tiflags & TH_ACK) {
tp->snd_una = ti->ti_ack;
if (SEQ_LT(tp->snd_nxt, tp->snd_una))
tp->snd_nxt = tp->snd_una;
}
tp->t_timer[TCPT_REXMT] = 0;
tp->irs = ti->ti_seq;
tcp_rcvseqinit(tp);
tp->t_flags |= TF_ACKNOW;
if (tiflags & TH_ACK && SEQ_GT(tp->snd_una, tp->iss)) {
STAT(tcpstat.tcps_connects++);
soisfconnected(so);
tp->t_state = TCPS_ESTABLISHED;
/* Do window scaling on this connection? */
/* if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
* (TF_RCVD_SCALE|TF_REQ_SCALE)) {
* tp->snd_scale = tp->requested_s_scale;
* tp->rcv_scale = tp->request_r_scale;
* }
*/
(void) tcp_reass(tp, (struct tcpiphdr *)0,
(struct mbuf *)0);
/*
* if we didn't have to retransmit the SYN,
* use its rtt as our initial srtt & rtt var.
*/
if (tp->t_rtt)
tcp_xmit_timer(tp, tp->t_rtt);
} else
tp->t_state = TCPS_SYN_RECEIVED;
trimthenstep6:
/*
* Advance ti->ti_seq to correspond to first data byte.
* If data, trim to stay within window,
* dropping FIN if necessary.
*/
ti->ti_seq++;
if (ti->ti_len > tp->rcv_wnd) {
todrop = ti->ti_len - tp->rcv_wnd;
m_adj(m, -todrop);
ti->ti_len = tp->rcv_wnd;
tiflags &= ~TH_FIN;
STAT(tcpstat.tcps_rcvpackafterwin++);
STAT(tcpstat.tcps_rcvbyteafterwin += todrop);
}
tp->snd_wl1 = ti->ti_seq - 1;
tp->rcv_up = ti->ti_seq;
goto step6;
} /* switch tp->t_state */
/*
* States other than LISTEN or SYN_SENT.
* First check timestamp, if present.
* Then check that at least some bytes of segment are within
* receive window. If segment begins before rcv_nxt,
* drop leading data (and SYN); if nothing left, just ack.
*
* RFC 1323 PAWS: If we have a timestamp reply on this segment
* and it's less than ts_recent, drop it.
*/
/* if (ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent &&
* TSTMP_LT(ts_val, tp->ts_recent)) {
*
*/ /* Check to see if ts_recent is over 24 days old. */
/* if ((int)(tcp_now - tp->ts_recent_age) > TCP_PAWS_IDLE) {
*/ /*
* * Invalidate ts_recent. If this segment updates
* * ts_recent, the age will be reset later and ts_recent
* * will get a valid value. If it does not, setting
* * ts_recent to zero will at least satisfy the
* * requirement that zero be placed in the timestamp
* * echo reply when ts_recent isn't valid. The
* * age isn't reset until we get a valid ts_recent
* * because we don't want out-of-order segments to be
* * dropped when ts_recent is old.
* */
/* tp->ts_recent = 0;
* } else {
* tcpstat.tcps_rcvduppack++;
* tcpstat.tcps_rcvdupbyte += ti->ti_len;
* tcpstat.tcps_pawsdrop++;
* goto dropafterack;
* }
* }
*/
todrop = tp->rcv_nxt - ti->ti_seq;
if (todrop > 0) {
if (tiflags & TH_SYN) {
tiflags &= ~TH_SYN;
ti->ti_seq++;
if (ti->ti_urp > 1)
ti->ti_urp--;
else
tiflags &= ~TH_URG;
todrop--;
}
/*
* Following if statement from Stevens, vol. 2, p. 960.
*/
if (todrop > ti->ti_len
|| (todrop == ti->ti_len && (tiflags & TH_FIN) == 0)) {
/*
* Any valid FIN must be to the left of the window.
* At this point the FIN must be a duplicate or out
* of sequence; drop it.
*/
tiflags &= ~TH_FIN;
/*
* Send an ACK to resynchronize and drop any data.
* But keep on processing for RST or ACK.
*/
tp->t_flags |= TF_ACKNOW;
todrop = ti->ti_len;
STAT(tcpstat.tcps_rcvduppack++);
STAT(tcpstat.tcps_rcvdupbyte += todrop);
} else {
STAT(tcpstat.tcps_rcvpartduppack++);
STAT(tcpstat.tcps_rcvpartdupbyte += todrop);
}
m_adj(m, todrop);
ti->ti_seq += todrop;
ti->ti_len -= todrop;
if (ti->ti_urp > todrop)
ti->ti_urp -= todrop;
else {
tiflags &= ~TH_URG;
ti->ti_urp = 0;
}
}
/*
* If new data are received on a connection after the
* user processes are gone, then RST the other end.
*/
if ((so->so_state & SS_NOFDREF) &&
tp->t_state > TCPS_CLOSE_WAIT && ti->ti_len) {
tp = tcp_close(tp);
STAT(tcpstat.tcps_rcvafterclose++);
goto dropwithreset;
}
/*
* If segment ends after window, drop trailing data
* (and PUSH and FIN); if nothing left, just ACK.
*/
todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd);
if (todrop > 0) {
STAT(tcpstat.tcps_rcvpackafterwin++);
if (todrop >= ti->ti_len) {
STAT(tcpstat.tcps_rcvbyteafterwin += ti->ti_len);
/*
* If a new connection request is received
* while in TIME_WAIT, drop the old connection
* and start over if the sequence numbers
* are above the previous ones.
*/
if (tiflags & TH_SYN &&
tp->t_state == TCPS_TIME_WAIT &&
SEQ_GT(ti->ti_seq, tp->rcv_nxt)) {
iss = tp->rcv_nxt + TCP_ISSINCR;
tp = tcp_close(tp);
goto findso;
}
/*
* If window is closed can only take segments at
* window edge, and have to drop data and PUSH from
* incoming segments. Continue processing, but
* remember to ack. Otherwise, drop segment
* and ack.
*/
if (tp->rcv_wnd == 0 && ti->ti_seq == tp->rcv_nxt) {
tp->t_flags |= TF_ACKNOW;
STAT(tcpstat.tcps_rcvwinprobe++);
} else
goto dropafterack;
} else
STAT(tcpstat.tcps_rcvbyteafterwin += todrop);
m_adj(m, -todrop);
ti->ti_len -= todrop;
tiflags &= ~(TH_PUSH|TH_FIN);
}
/*
* If last ACK falls within this segment's sequence numbers,
* record its timestamp.
*/
/* if (ts_present && SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) &&
* SEQ_LT(tp->last_ack_sent, ti->ti_seq + ti->ti_len +
* ((tiflags & (TH_SYN|TH_FIN)) != 0))) {
* tp->ts_recent_age = tcp_now;
* tp->ts_recent = ts_val;
* }
*/
/*
* If the RST bit is set examine the state:
* SYN_RECEIVED STATE:
* If passive open, return to LISTEN state.
* If active open, inform user that connection was refused.
* ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
* Inform user that connection was reset, and close tcb.
* CLOSING, LAST_ACK, TIME_WAIT STATES
* Close the tcb.
*/
if (tiflags&TH_RST) switch (tp->t_state) {
case TCPS_SYN_RECEIVED:
/* so->so_error = ECONNREFUSED; */
goto close;
case TCPS_ESTABLISHED:
case TCPS_FIN_WAIT_1:
case TCPS_FIN_WAIT_2:
case TCPS_CLOSE_WAIT:
/* so->so_error = ECONNRESET; */
close:
tp->t_state = TCPS_CLOSED;
STAT(tcpstat.tcps_drops++);
tp = tcp_close(tp);
goto drop;
case TCPS_CLOSING:
case TCPS_LAST_ACK:
case TCPS_TIME_WAIT:
tp = tcp_close(tp);
goto drop;
}
/*
* If a SYN is in the window, then this is an
* error and we send an RST and drop the connection.
*/
if (tiflags & TH_SYN) {
tp = tcp_drop(tp,0);
goto dropwithreset;
}
/*
* If the ACK bit is off we drop the segment and return.
*/
if ((tiflags & TH_ACK) == 0) goto drop;
/*
* Ack processing.
*/
switch (tp->t_state) {
/*
* In SYN_RECEIVED state if the ack ACKs our SYN then enter
* ESTABLISHED state and continue processing, otherwise
* send an RST. una<=ack<=max
*/
case TCPS_SYN_RECEIVED:
if (SEQ_GT(tp->snd_una, ti->ti_ack) ||
SEQ_GT(ti->ti_ack, tp->snd_max))
goto dropwithreset;
STAT(tcpstat.tcps_connects++);
tp->t_state = TCPS_ESTABLISHED;
/*
* The sent SYN is ack'ed with our sequence number +1
* The first data byte already in the buffer will get
* lost if no correction is made. This is only needed for
* SS_CTL since the buffer is empty otherwise.
* tp->snd_una++; or:
*/
tp->snd_una=ti->ti_ack;
if (so->so_state & SS_CTL) {
/* So tcp_ctl reports the right state */
ret = tcp_ctl(so);
if (ret == 1) {
soisfconnected(so);
so->so_state &= ~SS_CTL; /* success XXX */
} else if (ret == 2) {
so->so_state = SS_NOFDREF; /* CTL_CMD */
} else {
needoutput = 1;
tp->t_state = TCPS_FIN_WAIT_1;
}
} else {
soisfconnected(so);
}
/* Do window scaling? */
/* if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
* (TF_RCVD_SCALE|TF_REQ_SCALE)) {
* tp->snd_scale = tp->requested_s_scale;
* tp->rcv_scale = tp->request_r_scale;
* }
*/
(void) tcp_reass(tp, (struct tcpiphdr *)0, (struct mbuf *)0);
tp->snd_wl1 = ti->ti_seq - 1;
/* Avoid ack processing; snd_una==ti_ack => dup ack */
goto synrx_to_est;
/* fall into ... */
/*
* In ESTABLISHED state: drop duplicate ACKs; ACK out of range
* ACKs. If the ack is in the range
* tp->snd_una < ti->ti_ack <= tp->snd_max
* then advance tp->snd_una to ti->ti_ack and drop
* data from the retransmission queue. If this ACK reflects
* more up to date window information we update our window information.
*/
case TCPS_ESTABLISHED:
case TCPS_FIN_WAIT_1:
case TCPS_FIN_WAIT_2:
case TCPS_CLOSE_WAIT:
case TCPS_CLOSING:
case TCPS_LAST_ACK:
case TCPS_TIME_WAIT:
if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) {
if (ti->ti_len == 0 && tiwin == tp->snd_wnd) {
STAT(tcpstat.tcps_rcvdupack++);
DEBUG_MISC((dfd," dup ack m = %lx so = %lx \n",
(long )m, (long )so));
/*
* If we have outstanding data (other than
* a window probe), this is a completely
* duplicate ack (ie, window info didn't
* change), the ack is the biggest we've
* seen and we've seen exactly our rexmt
* threshold of them, assume a packet
* has been dropped and retransmit it.
* Kludge snd_nxt & the congestion
* window so we send only this one
* packet.
*
* We know we're losing at the current
* window size so do congestion avoidance
* (set ssthresh to half the current window
* and pull our congestion window back to
* the new ssthresh).
*
* Dup acks mean that packets have left the
* network (they're now cached at the receiver)
* so bump cwnd by the amount in the receiver
* to keep a constant cwnd packets in the
* network.
*/
if (tp->t_timer[TCPT_REXMT] == 0 ||
ti->ti_ack != tp->snd_una)
tp->t_dupacks = 0;
else if (++tp->t_dupacks == TCPREXMTTHRESH) {
tcp_seq onxt = tp->snd_nxt;
u_int win =
min(tp->snd_wnd, tp->snd_cwnd) / 2 /
tp->t_maxseg;
if (win < 2)
win = 2;
tp->snd_ssthresh = win * tp->t_maxseg;
tp->t_timer[TCPT_REXMT] = 0;
tp->t_rtt = 0;
tp->snd_nxt = ti->ti_ack;
tp->snd_cwnd = tp->t_maxseg;
(void) tcp_output(tp);
tp->snd_cwnd = tp->snd_ssthresh +
tp->t_maxseg * tp->t_dupacks;
if (SEQ_GT(onxt, tp->snd_nxt))
tp->snd_nxt = onxt;
goto drop;
} else if (tp->t_dupacks > TCPREXMTTHRESH) {
tp->snd_cwnd += tp->t_maxseg;
(void) tcp_output(tp);
goto drop;
}
} else
tp->t_dupacks = 0;
break;
}
synrx_to_est:
/*
* If the congestion window was inflated to account
* for the other side's cached packets, retract it.
*/
if (tp->t_dupacks > TCPREXMTTHRESH &&
tp->snd_cwnd > tp->snd_ssthresh)
tp->snd_cwnd = tp->snd_ssthresh;
tp->t_dupacks = 0;
if (SEQ_GT(ti->ti_ack, tp->snd_max)) {
STAT(tcpstat.tcps_rcvacktoomuch++);
goto dropafterack;
}
acked = ti->ti_ack - tp->snd_una;
STAT(tcpstat.tcps_rcvackpack++);
STAT(tcpstat.tcps_rcvackbyte += acked);
/*
* If we have a timestamp reply, update smoothed
* round trip time. If no timestamp is present but
* transmit timer is running and timed sequence
* number was acked, update smoothed round trip time.
* Since we now have an rtt measurement, cancel the
* timer backoff (cf., Phil Karn's retransmit alg.).
* Recompute the initial retransmit timer.
*/
/* if (ts_present)
* tcp_xmit_timer(tp, tcp_now-ts_ecr+1);
* else
*/
if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq))
tcp_xmit_timer(tp,tp->t_rtt);
/*
* If all outstanding data is acked, stop retransmit
* timer and remember to restart (more output or persist).
* If there is more data to be acked, restart retransmit
* timer, using current (possibly backed-off) value.
*/
if (ti->ti_ack == tp->snd_max) {
tp->t_timer[TCPT_REXMT] = 0;
needoutput = 1;
} else if (tp->t_timer[TCPT_PERSIST] == 0)
tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
/*
* When new data is acked, open the congestion window.
* If the window gives us less than ssthresh packets
* in flight, open exponentially (maxseg per packet).
* Otherwise open linearly: maxseg per window
* (maxseg^2 / cwnd per packet).
*/
{
register u_int cw = tp->snd_cwnd;
register u_int incr = tp->t_maxseg;
if (cw > tp->snd_ssthresh)
incr = incr * incr / cw;
tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);
}
if (acked > so->so_snd.sb_cc) {
tp->snd_wnd -= so->so_snd.sb_cc;
sbdrop(&so->so_snd, (int )so->so_snd.sb_cc);
ourfinisacked = 1;
} else {
sbdrop(&so->so_snd, acked);
tp->snd_wnd -= acked;
ourfinisacked = 0;
}
/*
* XXX sowwakup is called when data is acked and there's room for
* for more data... it should read() the socket
*/
/* if (so->so_snd.sb_flags & SB_NOTIFY)
* sowwakeup(so);
*/
tp->snd_una = ti->ti_ack;
if (SEQ_LT(tp->snd_nxt, tp->snd_una))
tp->snd_nxt = tp->snd_una;
switch (tp->t_state) {
/*
* In FIN_WAIT_1 STATE in addition to the processing
* for the ESTABLISHED state if our FIN is now acknowledged
* then enter FIN_WAIT_2.
*/
case TCPS_FIN_WAIT_1:
if (ourfinisacked) {
/*
* If we can't receive any more
* data, then closing user can proceed.
* Starting the timer is contrary to the
* specification, but if we don't get a FIN
* we'll hang forever.
*/
if (so->so_state & SS_FCANTRCVMORE) {
soisfdisconnected(so);
tp->t_timer[TCPT_2MSL] = TCP_MAXIDLE;
}
tp->t_state = TCPS_FIN_WAIT_2;
}
break;
/*
* In CLOSING STATE in addition to the processing for
* the ESTABLISHED state if the ACK acknowledges our FIN
* then enter the TIME-WAIT state, otherwise ignore
* the segment.
*/
case TCPS_CLOSING:
if (ourfinisacked) {
tp->t_state = TCPS_TIME_WAIT;
tcp_canceltimers(tp);
tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
soisfdisconnected(so);
}
break;
/*
* In LAST_ACK, we may still be waiting for data to drain
* and/or to be acked, as well as for the ack of our FIN.
* If our FIN is now acknowledged, delete the TCB,
* enter the closed state and return.
*/
case TCPS_LAST_ACK:
if (ourfinisacked) {
tp = tcp_close(tp);
goto drop;
}
break;
/*
* In TIME_WAIT state the only thing that should arrive
* is a retransmission of the remote FIN. Acknowledge
* it and restart the finack timer.
*/
case TCPS_TIME_WAIT:
tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
goto dropafterack;
}
} /* switch(tp->t_state) */
step6:
/*
* Update window information.
* Don't look at window if no ACK: TAC's send garbage on first SYN.
*/
if ((tiflags & TH_ACK) &&
(SEQ_LT(tp->snd_wl1, ti->ti_seq) ||
(tp->snd_wl1 == ti->ti_seq && (SEQ_LT(tp->snd_wl2, ti->ti_ack) ||
(tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd))))) {
/* keep track of pure window updates */
if (ti->ti_len == 0 &&
tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd)
STAT(tcpstat.tcps_rcvwinupd++);
tp->snd_wnd = tiwin;
tp->snd_wl1 = ti->ti_seq;
tp->snd_wl2 = ti->ti_ack;
if (tp->snd_wnd > tp->max_sndwnd)
tp->max_sndwnd = tp->snd_wnd;
needoutput = 1;
}
/*
* Process segments with URG.
*/
if ((tiflags & TH_URG) && ti->ti_urp &&
TCPS_HAVERCVDFIN(tp->t_state) == 0) {
/*
* This is a kludge, but if we receive and accept
* random urgent pointers, we'll crash in
* soreceive. It's hard to imagine someone
* actually wanting to send this much urgent data.
*/
if (ti->ti_urp + so->so_rcv.sb_cc > so->so_rcv.sb_datalen) {
ti->ti_urp = 0;
tiflags &= ~TH_URG;
goto dodata;
}
/*
* If this segment advances the known urgent pointer,
* then mark the data stream. This should not happen
* in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
* a FIN has been received from the remote side.
* In these states we ignore the URG.
*
* According to RFC961 (Assigned Protocols),
* the urgent pointer points to the last octet
* of urgent data. We continue, however,
* to consider it to indicate the first octet
* of data past the urgent section as the original
* spec states (in one of two places).
*/
if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {
tp->rcv_up = ti->ti_seq + ti->ti_urp;
so->so_urgc = so->so_rcv.sb_cc +
(tp->rcv_up - tp->rcv_nxt); /* -1; */
tp->rcv_up = ti->ti_seq + ti->ti_urp;
}
} else
/*
* If no out of band data is expected,
* pull receive urgent pointer along
* with the receive window.
*/
if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
tp->rcv_up = tp->rcv_nxt;
dodata:
/*
* Process the segment text, merging it into the TCP sequencing queue,
* and arranging for acknowledgment of receipt if necessary.
* This process logically involves adjusting tp->rcv_wnd as data
* is presented to the user (this happens in tcp_usrreq.c,
* case PRU_RCVD). If a FIN has already been received on this
* connection then we just ignore the text.
*/
if ((ti->ti_len || (tiflags&TH_FIN)) &&
TCPS_HAVERCVDFIN(tp->t_state) == 0) {
TCP_REASS(tp, ti, m, so, tiflags);
/*
* Note the amount of data that peer has sent into
* our window, in order to estimate the sender's
* buffer size.
*/
len = so->so_rcv.sb_datalen - (tp->rcv_adv - tp->rcv_nxt);
} else {
m_free(m);
tiflags &= ~TH_FIN;
}
/*
* If FIN is received ACK the FIN and let the user know
* that the connection is closing.
*/
if (tiflags & TH_FIN) {
if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
/*
* If we receive a FIN we can't send more data,
* set it SS_FDRAIN
* Shutdown the socket if there is no rx data in the
* buffer.
* soread() is called on completion of shutdown() and
* will got to TCPS_LAST_ACK, and use tcp_output()
* to send the FIN.
*/
/* sofcantrcvmore(so); */
sofwdrain(so);
tp->t_flags |= TF_ACKNOW;
tp->rcv_nxt++;
}
switch (tp->t_state) {
/*
* In SYN_RECEIVED and ESTABLISHED STATES
* enter the CLOSE_WAIT state.
*/
case TCPS_SYN_RECEIVED:
case TCPS_ESTABLISHED:
if(so->so_emu == EMU_CTL) /* no shutdown on socket */
tp->t_state = TCPS_LAST_ACK;
else
tp->t_state = TCPS_CLOSE_WAIT;
break;
/*
* If still in FIN_WAIT_1 STATE FIN has not been acked so
* enter the CLOSING state.
*/
case TCPS_FIN_WAIT_1:
tp->t_state = TCPS_CLOSING;
break;
/*
* In FIN_WAIT_2 state enter the TIME_WAIT state,
* starting the time-wait timer, turning off the other
* standard timers.
*/
case TCPS_FIN_WAIT_2:
tp->t_state = TCPS_TIME_WAIT;
tcp_canceltimers(tp);
tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
soisfdisconnected(so);
break;
/*
* In TIME_WAIT state restart the 2 MSL time_wait timer.
*/
case TCPS_TIME_WAIT:
tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
break;
}
}
/*
* If this is a small packet, then ACK now - with Nagel
* congestion avoidance sender won't send more until
* he gets an ACK.
*
* See above.
*/
/* if (ti->ti_len && (unsigned)ti->ti_len < tp->t_maxseg) {
*/
/* if ((ti->ti_len && (unsigned)ti->ti_len < tp->t_maxseg &&
* (so->so_iptos & IPTOS_LOWDELAY) == 0) ||
* ((so->so_iptos & IPTOS_LOWDELAY) &&
* ((struct tcpiphdr_2 *)ti)->first_char == (char)27)) {
*/
if (ti->ti_len && (unsigned)ti->ti_len <= 5 &&
((struct tcpiphdr_2 *)ti)->first_char == (char)27) {
tp->t_flags |= TF_ACKNOW;
}
/*
* Return any desired output.
*/
if (needoutput || (tp->t_flags & TF_ACKNOW)) {
(void) tcp_output(tp);
}
return;
dropafterack:
/*
* Generate an ACK dropping incoming segment if it occupies
* sequence space, where the ACK reflects our state.
*/
if (tiflags & TH_RST)
goto drop;
m_freem(m);
tp->t_flags |= TF_ACKNOW;
(void) tcp_output(tp);
return;
dropwithreset:
/* reuses m if m!=NULL, m_free() unnecessary */
if (tiflags & TH_ACK)
tcp_respond(tp, ti, m, (tcp_seq)0, ti->ti_ack, TH_RST);
else {
if (tiflags & TH_SYN) ti->ti_len++;
tcp_respond(tp, ti, m, ti->ti_seq+ti->ti_len, (tcp_seq)0,
TH_RST|TH_ACK);
}
return;
drop:
/*
* Drop space held by incoming segment and return.
*/
m_free(m);
return;
}
/*
* Ip input routine. Checksum and byte swap header. If fragmented
* try to reassemble. Process options. Pass to next level.
*/
void
ip_input(struct mbuf *m)
{
register struct ip *ip;
int hlen;
DEBUG_CALL("ip_input");
DEBUG_ARG("m = %lx", (long)m);
DEBUG_ARG("m_len = %d", m->m_len);
STAT(ipstat.ips_total++);
if (m->m_len < (int)sizeof (struct ip)) {
STAT(ipstat.ips_toosmall++);
return;
}
ip = mtod(m, struct ip *);
if (ip->ip_v != IPVERSION) {
STAT(ipstat.ips_badvers++);
goto bad;
}
hlen = ip->ip_hl << 2;
if (hlen < (int)sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
STAT(ipstat.ips_badhlen++); /* or packet too short */
goto bad;
}
/* keep ip header intact for ICMP reply
* ip->ip_sum = cksum(m, hlen);
* if (ip->ip_sum) {
*/
if(cksum(m,hlen)) {
STAT(ipstat.ips_badsum++);
goto bad;
}
/*
* Convert fields to host representation.
*/
NTOHS(ip->ip_len);
if (ip->ip_len < hlen) {
STAT(ipstat.ips_badlen++);
goto bad;
}
NTOHS(ip->ip_id);
NTOHS(ip->ip_off);
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_len < ip->ip_len) {
STAT(ipstat.ips_tooshort++);
goto bad;
}
if (slirp_restrict) {
if (ip_geth(ip->ip_dst) != special_addr_ip) {
if (ip_getn(ip->ip_dst) == 0xffffffffu && ip->ip_p != IPPROTO_UDP)
goto bad;
} else {
int host = ip_geth(ip->ip_dst) & 0xff;
struct ex_list *ex_ptr;
if (host == 0xff)
goto bad;
for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next)
if (ex_ptr->ex_addr == host)
break;
if (!ex_ptr)
goto bad;
}
}
/* Should drop packet if mbuf too long? hmmm... */
if (m->m_len > ip->ip_len)
m_adj(m, ip->ip_len - m->m_len);
/* check ip_ttl for a correct ICMP reply */
if(ip->ip_ttl==0 || ip->ip_ttl==1) {
icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
goto bad;
}
/*
* Process options and, if not destined for us,
* ship it on. ip_dooptions returns 1 when an
* error was detected (causing an icmp message
* to be sent and the original packet to be freed).
*/
/* We do no IP options */
/* if (hlen > sizeof (struct ip) && ip_dooptions(m))
* goto next;
*/
/*
* If offset or IP_MF are set, must reassemble.
* Otherwise, nothing need be done.
* (We could look in the reassembly queue to see
* if the packet was previously fragmented,
* but it's not worth the time; just let them time out.)
*
* XXX This should fail, don't fragment yet
*/
if (ip->ip_off &~ IP_DF) {
register struct ipq *fp;
struct qlink *l;
/*
* Look for queue of fragments
* of this datagram.
*/
for (l = ipq.ip_link.next; l != &ipq.ip_link; l = l->next) {
fp = container_of(l, struct ipq, ip_link);
if (ip->ip_id == fp->ipq_id &&
ip_equal(ip->ip_src, fp->ipq_src) &&
ip_equal(ip->ip_dst, fp->ipq_dst) &&
ip->ip_p == fp->ipq_p)
goto found;
}
fp = NULL;
found:
/*
* Adjust ip_len to not reflect header,
* set ip_mff if more fragments are expected,
* convert offset of this to bytes.
*/
ip->ip_len -= hlen;
if (ip->ip_off & IP_MF)
ip->ip_tos |= 1;
else
ip->ip_tos &= ~1;
ip->ip_off <<= 3;
/*
* If datagram marked as having more fragments
* or if this is not the first fragment,
* attempt reassembly; if it succeeds, proceed.
*/
if (ip->ip_tos & 1 || ip->ip_off) {
STAT(ipstat.ips_fragments++);
ip = ip_reass(ip, fp);
if (ip == NULL)
return;
STAT(ipstat.ips_reassembled++);
m = dtom(ip);
} else if (fp)
ip_freef(fp);
} else
void
udp_input(register struct mbuf *m, int iphlen)
{
register struct ip *ip;
register struct udphdr *uh;
/* struct mbuf *opts = 0;*/
int len;
struct ip save_ip;
struct socket *so;
DEBUG_CALL("udp_input");
DEBUG_ARG("m = %lx", (long)m);
DEBUG_ARG("iphlen = %d", iphlen);
STAT(udpstat.udps_ipackets++);
/*
* Strip IP options, if any; should skip this,
* make available to user, and use on returned packets,
* but we don't yet have a way to check the checksum
* with options still present.
*/
if(iphlen > sizeof(struct ip)) {
ip_stripoptions(m, (struct mbuf *)0);
iphlen = sizeof(struct ip);
}
/*
* Get IP and UDP header together in first mbuf.
*/
ip = mtod(m, struct ip *);
uh = (struct udphdr *)((caddr_t)ip + iphlen);
/*
* Make mbuf data length reflect UDP length.
* If not enough data to reflect UDP length, drop.
*/
len = ntohs((u_int16_t)uh->uh_ulen);
if (ip->ip_len != len) {
if (len > ip->ip_len) {
STAT(udpstat.udps_badlen++);
goto bad;
}
m_adj(m, len - ip->ip_len);
ip->ip_len = len;
}
/*
* Save a copy of the IP header in case we want restore it
* for sending an ICMP error message in response.
*/
save_ip = *ip;
save_ip.ip_len+= iphlen; /* tcp_input subtracts this */
/*
* Checksum extended UDP header and data.
*/
if (UDPCKSUM && uh->uh_sum) {
memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
((struct ipovly *)ip)->ih_x1 = 0;
((struct ipovly *)ip)->ih_len = uh->uh_ulen;
/* keep uh_sum for ICMP reply
* uh->uh_sum = cksum(m, len + sizeof (struct ip));
* if (uh->uh_sum) {
*/
if(cksum(m, len + sizeof(struct ip))) {
STAT(udpstat.udps_badsum++);
goto bad;
}
}
/*
* handle DHCP/BOOTP
*/
if (port_geth(uh->uh_dport) == BOOTP_SERVER) {
bootp_input(m);
goto bad;
}
if (slirp_restrict)
goto bad;
/*
* handle TFTP
*/
if (port_geth(uh->uh_dport) == TFTP_SERVER) {
tftp_input(m);
goto bad;
}
/*
* Locate pcb for datagram.
*/
so = udp_last_so;
if (so->so_laddr_port != port_geth(uh->uh_sport) ||
so->so_laddr_ip != ip_geth(ip->ip_src)) {
struct socket *tmp;
for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) {
if (tmp->so_laddr_port == port_geth(uh->uh_sport) &&
tmp->so_laddr_ip == ip_geth(ip->ip_src)) {
tmp->so_faddr_ip = ip_geth(ip->ip_dst);
tmp->so_faddr_port = port_geth(uh->uh_dport);
so = tmp;
break;
}
}
if (tmp == &udb) {
so = NULL;
} else {
STAT(udpstat.udpps_pcbcachemiss++);
udp_last_so = so;
}
}
if (so == NULL) {
/*
* If there's no socket for this packet,
* create one
*/
if ((so = socreate()) == NULL) goto bad;
if(udp_attach(so) == -1) {
DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
errno,errno_str));
sofree(so);
goto bad;
}
/*
* Setup fields
*/
/* udp_last_so = so; */
so->so_laddr_ip = ip_geth(ip->ip_src);
so->so_laddr_port = port_geth(uh->uh_sport);
if ((so->so_iptos = udp_tos(so)) == 0)
so->so_iptos = ip->ip_tos;
/*
* XXXXX Here, check if it's in udpexec_list,
* and if it is, do the fork_exec() etc.
*/
}
so->so_faddr_ip = ip_geth(ip->ip_dst); /* XXX */
so->so_faddr_port = port_geth(uh->uh_dport); /* XXX */
iphlen += sizeof(struct udphdr);
m->m_len -= iphlen;
m->m_data += iphlen;
/*
* Now we sendto() the packet.
*/
if (so->so_emu)
udp_emu(so, m);
if(sosendto(so,m) == -1) {
m->m_len += iphlen;
m->m_data -= iphlen;
*ip=save_ip;
DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno, errno_str));
icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,errno_str);
}
m_free(so->so_m); /* used for ICMP if error on sorecvfrom */
/* restore the orig mbuf packet */
m->m_len += iphlen;
m->m_data -= iphlen;
*ip=save_ip;
so->so_m=m; /* ICMP backup */
return;
bad:
m_freem(m);
/* if (opts) m_freem(opts); */
return;
}