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Diffstat (limited to 'sys/netinet/tcp_syncache.c')
-rw-r--r--sys/netinet/tcp_syncache.c118
1 files changed, 43 insertions, 75 deletions
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
index 84d3c1070dfa..931383ce8826 100644
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -1020,12 +1020,15 @@ syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
* with auto sizing. This allows us to scale the
* receive buffer over a wide range while not losing
* any efficiency or fine granularity.
+ *
+ * RFC1323: The Window field in a SYN (i.e., a <SYN>
+ * or <SYN,ACK>) segment itself is never scaled.
*/
while (wscale < TCP_MAX_WINSHIFT &&
(0x1 << wscale) < tcp_minmss)
wscale++;
sc->sc_requested_r_scale = wscale;
- sc->sc_requested_s_scale = to->to_requested_s_scale;
+ sc->sc_requested_s_scale = to->to_wscale;
sc->sc_flags |= SCF_WINSCALE;
}
}
@@ -1097,8 +1100,8 @@ syncache_respond(struct syncache *sc, struct mbuf *m)
struct ip *ip = NULL;
struct tcphdr *th;
int optlen, error;
- u_int16_t tlen, hlen, mssopt;
- u_int8_t *optp;
+ u_int16_t hlen, tlen, mssopt;
+ struct tcpopt to;
#ifdef INET6
struct ip6_hdr *ip6 = NULL;
#endif
@@ -1108,33 +1111,16 @@ syncache_respond(struct syncache *sc, struct mbuf *m)
(sc->sc_inc.inc_isipv6) ? sizeof(struct ip6_hdr) :
#endif
sizeof(struct ip);
+ tlen = hlen + sizeof(struct tcphdr);
/* Determine MSS we advertize to other end of connection. */
mssopt = tcp_mssopt(&sc->sc_inc);
if (sc->sc_peer_mss)
mssopt = max( min(sc->sc_peer_mss, mssopt), tcp_minmss);
- /* Compute the size of the TCP options. */
- if (sc->sc_flags & SCF_NOOPT) {
- optlen = 0;
- } else {
- optlen = TCPOLEN_MAXSEG +
- ((sc->sc_flags & SCF_WINSCALE) ? 4 : 0) +
- ((sc->sc_flags & SCF_TIMESTAMP) ? TCPOLEN_TSTAMP_APPA : 0);
-#ifdef TCP_SIGNATURE
- if (sc->sc_flags & SCF_SIGNATURE)
- optlen += TCPOLEN_SIGNATURE;
-#endif
- if (sc->sc_flags & SCF_SACK)
- optlen += TCPOLEN_SACK_PERMITTED;
- optlen = roundup2(optlen, 4);
- }
- tlen = hlen + sizeof(struct tcphdr) + optlen;
-
- /*
- * XXX: Assume that the entire packet will fit in a header mbuf.
- */
- KASSERT(max_linkhdr + tlen <= MHLEN, ("syncache: mbuf too small"));
+ /* XXX: Assume that the entire packet will fit in a header mbuf. */
+ KASSERT(max_linkhdr + tlen + MAX_TCPOPTLEN <= MHLEN,
+ ("syncache: mbuf too small"));
/* Create the IP+TCP header from scratch. */
if (m)
@@ -1197,70 +1183,52 @@ syncache_respond(struct syncache *sc, struct mbuf *m)
th->th_seq = htonl(sc->sc_iss);
th->th_ack = htonl(sc->sc_irs + 1);
- th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
+ th->th_off = sizeof(struct tcphdr) >> 2;
th->th_x2 = 0;
th->th_flags = TH_SYN|TH_ACK;
th->th_win = htons(sc->sc_wnd);
th->th_urp = 0;
/* Tack on the TCP options. */
- if (optlen != 0) {
- optp = (u_int8_t *)(th + 1);
- *optp++ = TCPOPT_MAXSEG;
- *optp++ = TCPOLEN_MAXSEG;
- *optp++ = (mssopt >> 8) & 0xff;
- *optp++ = mssopt & 0xff;
+ if ((sc->sc_flags & SCF_NOOPT) == 0) {
+ to.to_flags = 0;
+ to.to_mss = mssopt;
+ to.to_flags = TOF_MSS;
if (sc->sc_flags & SCF_WINSCALE) {
- *((u_int32_t *)optp) = htonl(TCPOPT_NOP << 24 |
- TCPOPT_WINDOW << 16 | TCPOLEN_WINDOW << 8 |
- sc->sc_requested_r_scale);
- optp += 4;
+ to.to_wscale = sc->sc_requested_r_scale;
+ to.to_flags |= TOF_SCALE;
}
-
if (sc->sc_flags & SCF_TIMESTAMP) {
- u_int32_t *lp = (u_int32_t *)(optp);
-
- /* Form timestamp option per appendix A of RFC 1323. */
- *lp++ = htonl(TCPOPT_TSTAMP_HDR);
- if (sc->sc_ts)
- *lp++ = htonl(sc->sc_ts);
- else
- *lp++ = htonl(ticks);
- *lp = htonl(sc->sc_tsreflect);
- optp += TCPOLEN_TSTAMP_APPA;
+ /* Virgin timestamp or TCP cookie enhanced one. */
+ to.to_tsval = sc->sc_ts ? sc->sc_ts : ticks;
+ to.to_tsecr = sc->sc_tsreflect;
+ to.to_flags |= TOF_TS;
}
-
+ if (sc->sc_flags & SCF_SACK)
+ to.to_flags |= TOF_SACKPERM;
#ifdef TCP_SIGNATURE
- /*
- * Handle TCP-MD5 passive opener response.
- */
- if (sc->sc_flags & SCF_SIGNATURE) {
- u_int8_t *bp = optp;
- int i;
-
- *bp++ = TCPOPT_SIGNATURE;
- *bp++ = TCPOLEN_SIGNATURE;
- for (i = 0; i < TCP_SIGLEN; i++)
- *bp++ = 0;
- tcp_signature_compute(m, sizeof(struct ip), 0, optlen,
- optp + 2, IPSEC_DIR_OUTBOUND);
- optp += TCPOLEN_SIGNATURE;
- }
-#endif /* TCP_SIGNATURE */
+ if (sc->sc_flags & SCF_SIGNATURE)
+ to.to_flags |= TOF_SIGNATURE;
+#endif
+ optlen = tcp_addoptions(&to, (u_char *)(th + 1));
- if (sc->sc_flags & SCF_SACK) {
- *optp++ = TCPOPT_SACK_PERMITTED;
- *optp++ = TCPOLEN_SACK_PERMITTED;
- }
+#ifdef TCP_SIGNATURE
+ tcp_signature_compute(m, sizeof(struct ip), 0, optlen,
+ to.to_signature, IPSEC_DIR_OUTBOUND);
+#endif
- {
- /* Pad TCP options to a 4 byte boundary */
- int padlen = optlen - (optp - (u_int8_t *)(th + 1));
- while (padlen-- > 0)
- *optp++ = TCPOPT_EOL;
- }
- }
+ /* Adjust headers by option size. */
+ th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
+ m->m_len += optlen;
+ m->m_pkthdr.len += optlen;
+#ifdef INET6
+ if (sc->sc_inc.inc_isipv6)
+ ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) + optlen);
+#endif
+ ip->ip_len += optlen;
+ } else
+ optlen = 0;
#ifdef INET6
if (sc->sc_inc.inc_isipv6) {
@@ -1272,7 +1240,7 @@ syncache_respond(struct syncache *sc, struct mbuf *m)
#endif
{
th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
- htons(tlen - hlen + IPPROTO_TCP));
+ htons(tlen + optlen - hlen + IPPROTO_TCP));
m->m_pkthdr.csum_flags = CSUM_TCP;
m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
error = ip_output(m, sc->sc_ipopts, NULL, 0, NULL, NULL);
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-28 18:20:20 +0000