Module Name: src
Committed By: maxv
Date: Wed Mar 28 14:43:55 UTC 2018
Modified Files:
src/sys/netinet: tcp_input.c
Log Message:
Several changes in syn_cache_respond:
* Replace idiotic diagnostic check by KASSERT. max_linkhdr+tlen<=MCLBYTES
is a widespread assumption.
* Improve initialization of 'tp'.
* Put panics in dead branches.
* Merge two switches.
To generate a diff of this commit:
cvs rdiff -u -r1.392 -r1.393 src/sys/netinet/tcp_input.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/netinet/tcp_input.c
diff -u src/sys/netinet/tcp_input.c:1.392 src/sys/netinet/tcp_input.c:1.393
--- src/sys/netinet/tcp_input.c:1.392 Wed Mar 28 14:30:42 2018
+++ src/sys/netinet/tcp_input.c Wed Mar 28 14:43:55 2018
@@ -1,4 +1,4 @@
-/* $NetBSD: tcp_input.c,v 1.392 2018/03/28 14:30:42 maxv Exp $ */
+/* $NetBSD: tcp_input.c,v 1.393 2018/03/28 14:43:55 maxv Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -148,7 +148,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.392 2018/03/28 14:30:42 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.393 2018/03/28 14:43:55 maxv Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -4370,7 +4370,7 @@ syn_cache_respond(struct syn_cache *sc)
#ifdef INET6
struct ip6_hdr *ip6 = NULL;
#endif
- struct tcpcb *tp = NULL;
+ struct tcpcb *tp;
struct tcphdr *th;
struct mbuf *m;
u_int hlen;
@@ -4393,17 +4393,13 @@ syn_cache_respond(struct syn_cache *sc)
return EAFNOSUPPORT;
}
- /* worst case scanario, since we don't know the option size yet */
+ /* Worst case scanario, since we don't know the option size yet. */
tlen = hlen + sizeof(struct tcphdr) + MAX_TCPOPTLEN;
+ KASSERT(max_linkhdr + tlen <= MCLBYTES);
/*
* Create the IP+TCP header from scratch.
*/
-#ifdef DIAGNOSTIC
- if (max_linkhdr + tlen > MCLBYTES)
- return ENOBUFS;
-#endif
-
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m && (max_linkhdr + tlen) > MHLEN) {
MCLGET(m, M_DONTWAIT);
@@ -4416,12 +4412,12 @@ syn_cache_respond(struct syn_cache *sc)
return ENOBUFS;
MCLAIM(m, &tcp_tx_mowner);
+ tp = sc->sc_tp;
+
/* Fixup the mbuf. */
m->m_data += max_linkhdr;
- if (sc->sc_tp)
- tp = sc->sc_tp;
m_reset_rcvif(m);
- memset(mtod(m, u_char *), 0, tlen);
+ memset(mtod(m, void *), 0, tlen);
switch (sc->sc_src.sa.sa_family) {
case AF_INET:
@@ -4448,7 +4444,7 @@ syn_cache_respond(struct syn_cache *sc)
break;
#endif
default:
- return ENOBUFS;
+ panic("%s: impossible (1)", __func__);
}
th->th_seq = htonl(sc->sc_iss);
@@ -4590,34 +4586,26 @@ syn_cache_respond(struct syn_cache *sc)
}
- /* Compute the packet's checksum. */
- switch (sc->sc_src.sa.sa_family) {
- case AF_INET:
- ip->ip_len = htons(tlen - hlen);
- th->th_sum = 0;
- th->th_sum = in4_cksum(m, IPPROTO_TCP, hlen, tlen - hlen);
- break;
-#ifdef INET6
- case AF_INET6:
- ip6->ip6_plen = htons(tlen - hlen);
- th->th_sum = 0;
- th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, tlen - hlen);
- break;
-#endif
- }
-
/*
+ * Compute the packet's checksum.
+ *
* Fill in some straggling IP bits. Note the stack expects
* ip_len to be in host order, for convenience.
*/
switch (sc->sc_src.sa.sa_family) {
case AF_INET:
+ ip->ip_len = htons(tlen - hlen);
+ th->th_sum = 0;
+ th->th_sum = in4_cksum(m, IPPROTO_TCP, hlen, tlen - hlen);
ip->ip_len = htons(tlen);
ip->ip_ttl = ip_defttl;
/* XXX tos? */
break;
#ifdef INET6
case AF_INET6:
+ ip6->ip6_plen = htons(tlen - hlen);
+ th->th_sum = 0;
+ th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, tlen - hlen);
ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
ip6->ip6_vfc |= IPV6_VERSION;
ip6->ip6_plen = htons(tlen - hlen);
@@ -4647,8 +4635,7 @@ syn_cache_respond(struct syn_cache *sc)
break;
#endif
default:
- error = EAFNOSUPPORT;
- break;
+ panic("%s: impossible (2)", __func__);
}
return error;
