diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c index 318fc261c8b8..d1303615154d 100644 --- a/sys/netinet/tcp_reass.c +++ b/sys/netinet/tcp_reass.c @@ -177,7 +177,9 @@ tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m) struct tseg_qent *nq; struct tseg_qent *te = NULL; struct socket *so = tp->t_inpcb->inp_socket; + char *s = NULL; int flags; + struct tseg_qent tqs; INP_WLOCK_ASSERT(tp->t_inpcb); @@ -215,19 +217,40 @@ tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m) TCPSTAT_INC(tcps_rcvmemdrop); m_freem(m); *tlenp = 0; + if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL))) { + log(LOG_DEBUG, "%s; %s: queue limit reached, " + "segment dropped\n", s, __func__); + free(s, M_TCPLOG); + } return (0); } /* * Allocate a new queue entry. If we can't, or hit the zone limit * just drop the pkt. + * + * Use a temporary structure on the stack for the missing segment + * when the zone is exhausted. Otherwise we may get stuck. */ te = uma_zalloc(V_tcp_reass_zone, M_NOWAIT); - if (te == NULL) { + if (te == NULL && th->th_seq != tp->rcv_nxt) { TCPSTAT_INC(tcps_rcvmemdrop); m_freem(m); *tlenp = 0; + if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL))) { + log(LOG_DEBUG, "%s; %s: global zone limit reached, " + "segment dropped\n", s, __func__); + free(s, M_TCPLOG); + } return (0); + } else if (th->th_seq == tp->rcv_nxt) { + bzero(&tqs, sizeof(struct tseg_qent)); + te = &tqs; + if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL))) { + log(LOG_DEBUG, "%s; %s: global zone limit reached, " + "using stack for missing segment\n", s, __func__); + free(s, M_TCPLOG); + } } tp->t_segqlen++; @@ -304,6 +327,8 @@ tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m) if (p == NULL) { LIST_INSERT_HEAD(&tp->t_segq, te, tqe_q); } else { + KASSERT(te != &tqs, ("%s: temporary stack based entry not " + "first element in queue", __func__)); LIST_INSERT_AFTER(p, te, tqe_q); } @@ -327,7 +352,8 @@ tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m) m_freem(q->tqe_m); else sbappendstream_locked(&so->so_rcv, q->tqe_m); - uma_zfree(V_tcp_reass_zone, q); + if (q != &tqs) + uma_zfree(V_tcp_reass_zone, q); tp->t_segqlen--; q = nq; } while (q && q->tqe_th->th_seq == tp->rcv_nxt);