diff options
| -rw-r--r-- | sys/netinet/tcp_output.c | 82 |
1 files changed, 49 insertions, 33 deletions
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c index 94b48fc..b5bc3d9 100644 --- a/sys/netinet/tcp_output.c +++ b/sys/netinet/tcp_output.c @@ -465,9 +465,8 @@ after_sack_rexmit: } /* - * Truncate to the maximum segment length or enable TCP Segmentation - * Offloading (if supported by hardware) and ensure that FIN is removed - * if the length no longer contains the last data byte. + * Decide if we can use TCP Segmentation Offloading (if supported by + * hardware). * * TSO may only be used if we are in a pure bulk sending state. The * presence of TCP-MD5, SACK retransmits, SACK advertizements and @@ -475,10 +474,6 @@ after_sack_rexmit: * (except for the sequence number) for all generated packets. This * makes it impossible to transmit any options which vary per generated * segment or packet. - * - * The length of TSO bursts is limited to TCP_MAXWIN. That limit and - * removal of FIN (if not already catched here) are handled later after - * the exact length of the TCP options are known. */ #ifdef IPSEC /* @@ -487,22 +482,15 @@ after_sack_rexmit: */ ipsec_optlen = ipsec_hdrsiz_tcp(tp); #endif - if (len > tp->t_maxseg) { - if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && - ((tp->t_flags & TF_SIGNATURE) == 0) && - tp->rcv_numsacks == 0 && sack_rxmit == 0 && - tp->t_inpcb->inp_options == NULL && - tp->t_inpcb->in6p_options == NULL + if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > tp->t_maxseg && + ((tp->t_flags & TF_SIGNATURE) == 0) && + tp->rcv_numsacks == 0 && sack_rxmit == 0 && #ifdef IPSEC - && ipsec_optlen == 0 + ipsec_optlen == 0 && #endif - ) { - tso = 1; - } else { - len = tp->t_maxseg; - sendalot = 1; - } - } + tp->t_inpcb->inp_options == NULL && + tp->t_inpcb->in6p_options == NULL) + tso = 1; if (sack_rxmit) { if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc)) @@ -732,28 +720,53 @@ send: * bump the packet length beyond the t_maxopd length. * Clear the FIN bit because we cut off the tail of * the segment. - * - * When doing TSO limit a burst to TCP_MAXWIN minus the - * IP, TCP and Options length to keep ip->ip_len from - * overflowing. Prevent the last segment from being - * fractional thus making them all equal sized and set - * the flag to continue sending. TSO is disabled when - * IP options or IPSEC are present. */ if (len + optlen + ipoptlen > tp->t_maxopd) { flags &= ~TH_FIN; + if (tso) { - if (len > TCP_MAXWIN - hdrlen - optlen) { - len = TCP_MAXWIN - hdrlen - optlen; - len = len - (len % (tp->t_maxopd - optlen)); + KASSERT(ipoptlen == 0, + ("%s: TSO can't do IP options", __func__)); + + /* + * Limit a burst to IP_MAXPACKET minus IP, + * TCP and options length to keep ip->ip_len + * from overflowing. + */ + if (len > IP_MAXPACKET - hdrlen) { + len = IP_MAXPACKET - hdrlen; + sendalot = 1; + } + + /* + * Prevent the last segment from being + * fractional unless the send sockbuf can + * be emptied. + */ + if (sendalot && off + len < so->so_snd.sb_cc) { + len -= len % (tp->t_maxopd - optlen); sendalot = 1; - } else if (tp->t_flags & TF_NEEDFIN) + } + + /* + * Send the FIN in a separate segment + * after the bulk sending is done. + * We don't trust the TSO implementations + * to clear the FIN flag on all but the + * last segment. + */ + if (tp->t_flags & TF_NEEDFIN) sendalot = 1; + } else { len = tp->t_maxopd - optlen - ipoptlen; sendalot = 1; } - } + } else + tso = 0; + + KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET, + ("%s: len > IP_MAXPACKET", __func__)); /*#ifdef DIAGNOSTIC*/ #ifdef INET6 @@ -1068,6 +1081,9 @@ send: m->m_pkthdr.tso_segsz = tp->t_maxopd - optlen; } + KASSERT(len + hdrlen + ipoptlen == m_length(m, NULL), + ("%s: mbuf chain shorter than expected", __func__)); + /* * In transmit state, time the transmission and arrange for * the retransmit. In persist state, just set snd_max. |
