git: 7d2608a5d24e - main - tcp: Make error handling in tcp_usr_send() more consistent
Mark Johnston
markj at FreeBSD.org
Fri May 21 21:45:30 UTC 2021
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=7d2608a5d24ec3534dad7f24191f12a8181ea206
commit 7d2608a5d24ec3534dad7f24191f12a8181ea206
Author: Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-05-21 21:44:40 +0000
Commit: Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-05-21 21:45:18 +0000
tcp: Make error handling in tcp_usr_send() more consistent
- Free the input mbuf in a single place instead of in every error path.
- Handle PRUS_NOTREADY consistently.
- Flush the socket's send buffer if an implicit connect fails. At that
point the mbuf has already been enqueued but we don't want to keep it
in the send buffer.
Reviewed by: gallatin, tuexen
Discussed with: jhb
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30349
---
sys/netinet/tcp_usrreq.c | 67 +++++++++++++++++++-----------------------------
1 file changed, 26 insertions(+), 41 deletions(-)
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
index 693cf553de44..37bedc0125c9 100644
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -993,13 +993,6 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
if (control)
m_freem(control);
-
- /*
- * In case of PRUS_NOTREADY, tcp_usr_ready() is responsible
- * for freeing memory.
- */
- if ((flags & PRUS_NOTREADY) == 0)
- m_freem(m);
error = ECONNRESET;
goto out;
}
@@ -1007,7 +1000,6 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
/* TCP doesn't do control messages (rights, creds, etc) */
if (control->m_len) {
m_freem(control);
- m_freem(m);
error = EINVAL;
goto out;
}
@@ -1015,13 +1007,10 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
control = NULL;
}
tp = intotcpcb(inp);
- if (flags & PRUS_OOB) {
- if ((error = tcp_pru_options_support(tp, PRUS_OOB)) != 0) {
- if ((flags & PRUS_NOTREADY) == 0)
- m_freem(m);
- goto out;
- }
- }
+ if ((flags & PRUS_OOB) != 0 &&
+ (error = tcp_pru_options_support(tp, PRUS_OOB)) != 0)
+ goto out;
+
TCPDEBUG1();
if (nam != NULL && tp->t_state < TCPS_SYN_SENT) {
switch (nam->sa_family) {
@@ -1029,30 +1018,24 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
case AF_INET:
sinp = (struct sockaddr_in *)nam;
if (sinp->sin_len != sizeof(struct sockaddr_in)) {
- m_freem(m);
error = EINVAL;
goto out;
}
if ((inp->inp_vflag & INP_IPV6) != 0) {
- m_freem(m);
error = EAFNOSUPPORT;
goto out;
}
if (IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
- m_freem(m);
error = EAFNOSUPPORT;
goto out;
}
if (ntohl(sinp->sin_addr.s_addr) == INADDR_BROADCAST) {
- m_freem(m);
error = EACCES;
goto out;
}
if ((error = prison_remote_ip4(td->td_ucred,
- &sinp->sin_addr))) {
- m_freem(m);
+ &sinp->sin_addr)))
goto out;
- }
#ifdef INET6
isipv6 = 0;
#endif
@@ -1065,17 +1048,14 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
sin6 = (struct sockaddr_in6 *)nam;
if (sin6->sin6_len != sizeof(*sin6)) {
- m_freem(m);
error = EINVAL;
goto out;
}
if ((inp->inp_vflag & INP_IPV6PROTO) == 0) {
- m_freem(m);
error = EAFNOSUPPORT;
goto out;
}
if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) {
- m_freem(m);
error = EAFNOSUPPORT;
goto out;
}
@@ -1083,12 +1063,10 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
#ifdef INET
if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
error = EINVAL;
- m_freem(m);
goto out;
}
if ((inp->inp_vflag & INP_IPV4) == 0) {
error = EAFNOSUPPORT;
- m_freem(m);
goto out;
}
restoreflags = true;
@@ -1098,23 +1076,18 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
if (IN_MULTICAST(
ntohl(sinp->sin_addr.s_addr))) {
error = EAFNOSUPPORT;
- m_freem(m);
goto out;
}
if ((error = prison_remote_ip4(td->td_ucred,
- &sinp->sin_addr))) {
- m_freem(m);
+ &sinp->sin_addr)))
goto out;
- }
isipv6 = 0;
#else /* !INET */
error = EAFNOSUPPORT;
- m_freem(m);
goto out;
#endif /* INET */
} else {
if ((inp->inp_vflag & INP_IPV6) == 0) {
- m_freem(m);
error = EAFNOSUPPORT;
goto out;
}
@@ -1122,23 +1095,21 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
inp->inp_vflag &= ~INP_IPV4;
inp->inp_inc.inc_flags |= INC_ISIPV6;
if ((error = prison_remote_ip6(td->td_ucred,
- &sin6->sin6_addr))) {
- m_freem(m);
+ &sin6->sin6_addr)))
goto out;
- }
isipv6 = 1;
}
break;
}
#endif /* INET6 */
default:
- m_freem(m);
error = EAFNOSUPPORT;
goto out;
}
}
if (!(flags & PRUS_OOB)) {
sbappendstream(&so->so_snd, m, flags);
+ m = NULL;
if (nam && tp->t_state < TCPS_SYN_SENT) {
/*
* Do implied connect if not yet connected,
@@ -1164,8 +1135,11 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
if (error == 0 || inp->inp_lport != 0)
restoreflags = false;
- if (error)
+ if (error) {
+ /* m is freed if PRUS_NOTREADY is unset. */
+ sbflush(&so->so_snd);
goto out;
+ }
if (IS_FASTOPEN(tp->t_flags))
tcp_fastopen_connect(tp);
else {
@@ -1206,7 +1180,6 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
SOCKBUF_LOCK(&so->so_snd);
if (sbspace(&so->so_snd) < -512) {
SOCKBUF_UNLOCK(&so->so_snd);
- m_freem(m);
error = ENOBUFS;
goto out;
}
@@ -1220,6 +1193,7 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
*/
sbappendstream_locked(&so->so_snd, m, flags);
SOCKBUF_UNLOCK(&so->so_snd);
+ m = NULL;
if (nam && tp->t_state < TCPS_SYN_SENT) {
/*
* Do implied connect if not yet connected,
@@ -1251,13 +1225,16 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
if (error == 0 || inp->inp_lport != 0)
restoreflags = false;
- if (error)
+ if (error != 0) {
+ /* m is freed if PRUS_NOTREADY is unset. */
+ sbflush(&so->so_snd);
goto out;
+ }
tp->snd_wnd = TTCP_CLIENT_SND_WND;
tcp_mss(tp, -1);
}
tp->snd_up = tp->snd_una + sbavail(&so->so_snd);
- if (!(flags & PRUS_NOTREADY)) {
+ if ((flags & PRUS_NOTREADY) == 0) {
tp->t_flags |= TF_FORCEDATA;
error = tp->t_fb->tfb_tcp_output(tp);
tp->t_flags &= ~TF_FORCEDATA;
@@ -1268,7 +1245,15 @@ tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
&inp->inp_socket->so_snd,
TCP_LOG_USERSEND, error,
0, NULL, false);
+
out:
+ /*
+ * In case of PRUS_NOTREADY, the caller or tcp_usr_ready() is
+ * responsible for freeing memory.
+ */
+ if (m != NULL && (flags & PRUS_NOTREADY) == 0)
+ m_freem(m);
+
/*
* If the request was unsuccessful and we changed flags,
* restore the original flags.
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