From owner-dev-commits-src-all@freebsd.org Sun Feb 21 16:17:15 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 58E2A55AB52; Sun, 21 Feb 2021 16:17:15 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Dk9SW226Dz4rk0; Sun, 21 Feb 2021 16:17:15 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 3851C15C68; Sun, 21 Feb 2021 16:17:15 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 11LGHFT9000902; Sun, 21 Feb 2021 16:17:15 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 11LGHFdi000901; Sun, 21 Feb 2021 16:17:15 GMT (envelope-from git) Date: Sun, 21 Feb 2021 16:17:15 GMT Message-Id: <202102211617.11LGHFdi000901@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Michael Tuexen Subject: git: b963ce4588b3 - main - sctp: improve computation of an alternate net MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: tuexen X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: b963ce4588b33f733aef3f7a7f3fbe5018a89728 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Feb 2021 16:17:15 -0000 The branch main has been updated by tuexen: URL: https://cgit.FreeBSD.org/src/commit/?id=b963ce4588b33f733aef3f7a7f3fbe5018a89728 commit b963ce4588b33f733aef3f7a7f3fbe5018a89728 Author: Michael Tuexen AuthorDate: 2021-02-21 16:13:06 +0000 Commit: Michael Tuexen CommitDate: 2021-02-21 16:13:06 +0000 sctp: improve computation of an alternate net Espeially handle the case where the net passed in is about to be deleted and therefore not in the list of nets anymore. MFC after: 3 days Reported by: syzbot+9756917a7c8381adf5e8@syzkaller.appspotmail.com --- sys/netinet/sctp_timer.c | 85 ++++++++++++++++++++++++++++-------------------- 1 file changed, 49 insertions(+), 36 deletions(-) diff --git a/sys/netinet/sctp_timer.c b/sys/netinet/sctp_timer.c index bce1f5cd166d..582abd8e8854 100644 --- a/sys/netinet/sctp_timer.c +++ b/sys/netinet/sctp_timer.c @@ -164,8 +164,8 @@ sctp_threshold_management(struct sctp_inpcb *inp, struct sctp_tcb *stcb, } /* - * sctp_find_alternate_net() returns a non-NULL pointer as long - * the argument net is non-NULL. + * sctp_find_alternate_net() returns a non-NULL pointer as long as there + * exists nets, which are not being deleted. */ struct sctp_nets * sctp_find_alternate_net(struct sctp_tcb *stcb, @@ -174,14 +174,14 @@ sctp_find_alternate_net(struct sctp_tcb *stcb, { /* Find and return an alternate network if possible */ struct sctp_nets *alt, *mnet, *min_errors_net = NULL, *max_cwnd_net = NULL; - int once; + bool looped; /* JRS 5/14/07 - Initialize min_errors to an impossible value. */ int min_errors = -1; uint32_t max_cwnd = 0; if (stcb->asoc.numnets == 1) { - /* No others but net */ + /* No selection can be made. */ return (TAILQ_FIRST(&stcb->asoc.nets)); } /* @@ -328,25 +328,22 @@ sctp_find_alternate_net(struct sctp_tcb *stcb, return (max_cwnd_net); } } - mnet = net; - once = 0; - - if (mnet == NULL) { - mnet = TAILQ_FIRST(&stcb->asoc.nets); - if (mnet == NULL) { - return (NULL); - } + /* Look for an alternate net, which is active. */ + if ((net != NULL) && ((net->dest_state & SCTP_ADDR_BEING_DELETED) == 0)) { + alt = TAILQ_NEXT(net, sctp_next);; + } else { + alt = TAILQ_FIRST(&stcb->asoc.nets); } + looped = false; for (;;) { - alt = TAILQ_NEXT(mnet, sctp_next); if (alt == NULL) { - once++; - if (once > 1) { - break; + if (!looped) { + alt = TAILQ_FIRST(&stcb->asoc.nets); + looped = true; } - alt = TAILQ_FIRST(&stcb->asoc.nets); + /* Definitely out of candidates. */ if (alt == NULL) { - return (NULL); + break; } } if (alt->ro.ro_nh == NULL) { @@ -358,43 +355,59 @@ sctp_find_alternate_net(struct sctp_tcb *stcb, } if (((alt->dest_state & SCTP_ADDR_REACHABLE) == SCTP_ADDR_REACHABLE) && (alt->ro.ro_nh != NULL) && - (!(alt->dest_state & SCTP_ADDR_UNCONFIRMED))) { - /* Found a reachable address */ + (!(alt->dest_state & SCTP_ADDR_UNCONFIRMED)) && + (alt != net)) { + /* Found an alternate net, which is reachable. */ break; } - mnet = alt; + alt = TAILQ_NEXT(alt, sctp_next); } if (alt == NULL) { - /* Case where NO insv network exists (dormant state) */ - /* we rotate destinations */ - once = 0; - mnet = net; + /* + * In case no active alternate net has been found, look for + * an alternate net, which is confirmed. + */ + if ((net != NULL) && ((net->dest_state & SCTP_ADDR_BEING_DELETED) == 0)) { + alt = TAILQ_NEXT(net, sctp_next);; + } else { + alt = TAILQ_FIRST(&stcb->asoc.nets); + } + looped = false; for (;;) { - if (mnet == NULL) { - return (TAILQ_FIRST(&stcb->asoc.nets)); - } - alt = TAILQ_NEXT(mnet, sctp_next); if (alt == NULL) { - once++; - if (once > 1) { - break; + if (!looped) { + alt = TAILQ_FIRST(&stcb->asoc.nets); + looped = true; } - alt = TAILQ_FIRST(&stcb->asoc.nets); + /* Definitely out of candidates. */ if (alt == NULL) { break; } } if ((!(alt->dest_state & SCTP_ADDR_UNCONFIRMED)) && (alt != net)) { - /* Found an alternate address */ + /* + * Found an alternate net, which is + * confirmed. + */ break; } - mnet = alt; + alt = TAILQ_NEXT(alt, sctp_next); } } if (alt == NULL) { - return (net); + /* + * In case no confirmed alternate net has been found, just + * return net, if it is not being deleted. In the other case + * just return the first net. + */ + if ((net != NULL) && ((net->dest_state & SCTP_ADDR_BEING_DELETED) == 0)) { + alt = net; + } + if (alt == NULL) { + alt = TAILQ_FIRST(&stcb->asoc.nets); + } } return (alt); }