fedora core 6 1.2949 + vserver 2.2.0
[linux-2.6.git] / net / ipv4 / tcp_output.c
index 5dc3118..340bcdd 100644 (file)
 #include <linux/smp_lock.h>
 
 /* People can turn this off for buggy TCP's found in printers etc. */
-int sysctl_tcp_retrans_collapse = 1;
+int sysctl_tcp_retrans_collapse __read_mostly = 1;
 
 /* People can turn this on to  work with those rare, broken TCPs that
  * interpret the window field as a signed quantity.
  */
-int sysctl_tcp_workaround_signed_windows = 0;
+int sysctl_tcp_workaround_signed_windows __read_mostly = 0;
 
 /* This limits the percentage of the congestion window which we
  * will allow a single TSO frame to consume.  Building TSO frames
  * which are too large can cause TCP streams to be bursty.
  */
-int sysctl_tcp_tso_win_divisor = 3;
+int sysctl_tcp_tso_win_divisor __read_mostly = 3;
 
-int sysctl_tcp_mtu_probing = 0;
-int sysctl_tcp_base_mss = 512;
+int sysctl_tcp_mtu_probing __read_mostly = 0;
+int sysctl_tcp_base_mss __read_mostly = 512;
 
 /* By default, RFC2861 behavior.  */
-int sysctl_tcp_slow_start_after_idle = 1;
+int sysctl_tcp_slow_start_after_idle __read_mostly = 1;
 
 static void update_send_head(struct sock *sk, struct tcp_sock *tp,
                             struct sk_buff *skb)
@@ -269,14 +269,14 @@ static u16 tcp_select_window(struct sock *sk)
        return new_win;
 }
 
-static void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp,
-                                        __u32 tstamp)
+static void tcp_build_and_update_options(__be32 *ptr, struct tcp_sock *tp,
+                                        __u32 tstamp, __u8 **md5_hash)
 {
        if (tp->rx_opt.tstamp_ok) {
-               *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
-                                         (TCPOPT_NOP << 16) |
-                                         (TCPOPT_TIMESTAMP << 8) |
-                                         TCPOLEN_TIMESTAMP);
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_TIMESTAMP << 8) |
+                              TCPOLEN_TIMESTAMP);
                *ptr++ = htonl(tstamp);
                *ptr++ = htonl(tp->rx_opt.ts_recent);
        }
@@ -298,16 +298,29 @@ static void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp,
                        tp->rx_opt.eff_sacks--;
                }
        }
+#ifdef CONFIG_TCP_MD5SIG
+       if (md5_hash) {
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_MD5SIG << 8) |
+                              TCPOLEN_MD5SIG);
+               *md5_hash = (__u8 *)ptr;
+       }
+#endif
 }
 
 /* Construct a tcp options header for a SYN or SYN_ACK packet.
  * If this is every changed make sure to change the definition of
  * MAX_SYN_SIZE to match the new maximum number of options that you
  * can generate.
+ *
+ * Note - that with the RFC2385 TCP option, we make room for the
+ * 16 byte MD5 hash. This will be filled in later, so the pointer for the
+ * location to be filled is passed back up.
  */
-static void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack,
+static void tcp_syn_build_options(__be32 *ptr, int mss, int ts, int sack,
                                  int offer_wscale, int wscale, __u32 tstamp,
-                                 __u32 ts_recent)
+                                 __u32 ts_recent, __u8 **md5_hash)
 {
        /* We always get an MSS option.
         * The option bytes which will be seen in normal data
@@ -325,18 +338,41 @@ static void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack,
        *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss);
        if (ts) {
                if(sack)
-                       *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) |
-                                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
+                       *ptr++ = htonl((TCPOPT_SACK_PERM << 24) |
+                                      (TCPOLEN_SACK_PERM << 16) |
+                                      (TCPOPT_TIMESTAMP << 8) |
+                                      TCPOLEN_TIMESTAMP);
                else
-                       *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
-                                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
+                       *ptr++ = htonl((TCPOPT_NOP << 24) |
+                                      (TCPOPT_NOP << 16) |
+                                      (TCPOPT_TIMESTAMP << 8) |
+                                      TCPOLEN_TIMESTAMP);
                *ptr++ = htonl(tstamp);         /* TSVAL */
                *ptr++ = htonl(ts_recent);      /* TSECR */
        } else if(sack)
-               *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
-                                         (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM);
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_SACK_PERM << 8) |
+                              TCPOLEN_SACK_PERM);
        if (offer_wscale)
-               *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale));
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_WINDOW << 16) |
+                              (TCPOLEN_WINDOW << 8) |
+                              (wscale));
+#ifdef CONFIG_TCP_MD5SIG
+       /*
+        * If MD5 is enabled, then we set the option, and include the size
+        * (always 18). The actual MD5 hash is added just before the
+        * packet is sent.
+        */
+       if (md5_hash) {
+               *ptr++ = htonl((TCPOPT_NOP << 24) |
+                              (TCPOPT_NOP << 16) |
+                              (TCPOPT_MD5SIG << 8) |
+                              TCPOLEN_MD5SIG);
+               *md5_hash = (__u8 *) ptr;
+       }
+#endif
 }
 
 /* This routine actually transmits TCP packets queued in by
@@ -357,6 +393,10 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
        struct tcp_sock *tp;
        struct tcp_skb_cb *tcb;
        int tcp_header_size;
+#ifdef CONFIG_TCP_MD5SIG
+       struct tcp_md5sig_key *md5;
+       __u8 *md5_hash_location;
+#endif
        struct tcphdr *th;
        int sysctl_flags;
        int err;
@@ -415,6 +455,16 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
        if (tcp_packets_in_flight(tp) == 0)
                tcp_ca_event(sk, CA_EVENT_TX_START);
 
+#ifdef CONFIG_TCP_MD5SIG
+       /*
+        * Are we doing MD5 on this segment? If so - make
+        * room for it.
+        */
+       md5 = tp->af_specific->md5_lookup(sk, sk);
+       if (md5)
+               tcp_header_size += TCPOLEN_MD5SIG_ALIGNED;
+#endif
+
        th = (struct tcphdr *) skb_push(skb, tcp_header_size);
        skb->h.th = th;
        skb_set_owner_w(skb, sk);
@@ -424,14 +474,14 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
        th->dest                = inet->dport;
        th->seq                 = htonl(tcb->seq);
        th->ack_seq             = htonl(tp->rcv_nxt);
-       *(((__u16 *)th) + 6)    = htons(((tcp_header_size >> 2) << 12) |
+       *(((__be16 *)th) + 6)   = htons(((tcp_header_size >> 2) << 12) |
                                        tcb->flags);
 
        if (unlikely(tcb->flags & TCPCB_FLAG_SYN)) {
                /* RFC1323: The window in SYN & SYN/ACK segments
                 * is never scaled.
                 */
-               th->window      = htons(tp->rcv_wnd);
+               th->window      = htons(min(tp->rcv_wnd, 65535U));
        } else {
                th->window      = htons(tcp_select_window(sk));
        }
@@ -445,20 +495,41 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
        }
 
        if (unlikely(tcb->flags & TCPCB_FLAG_SYN)) {
-               tcp_syn_build_options((__u32 *)(th + 1),
+               tcp_syn_build_options((__be32 *)(th + 1),
                                      tcp_advertise_mss(sk),
                                      (sysctl_flags & SYSCTL_FLAG_TSTAMPS),
                                      (sysctl_flags & SYSCTL_FLAG_SACK),
                                      (sysctl_flags & SYSCTL_FLAG_WSCALE),
                                      tp->rx_opt.rcv_wscale,
                                      tcb->when,
-                                     tp->rx_opt.ts_recent);
+                                     tp->rx_opt.ts_recent,
+
+#ifdef CONFIG_TCP_MD5SIG
+                                     md5 ? &md5_hash_location :
+#endif
+                                     NULL);
        } else {
-               tcp_build_and_update_options((__u32 *)(th + 1),
-                                            tp, tcb->when);
+               tcp_build_and_update_options((__be32 *)(th + 1),
+                                            tp, tcb->when,
+#ifdef CONFIG_TCP_MD5SIG
+                                            md5 ? &md5_hash_location :
+#endif
+                                            NULL);
                TCP_ECN_send(sk, tp, skb, tcp_header_size);
        }
 
+#ifdef CONFIG_TCP_MD5SIG
+       /* Calculate the MD5 hash, as we have all we need now */
+       if (md5) {
+               tp->af_specific->calc_md5_hash(md5_hash_location,
+                                              md5,
+                                              sk, NULL, NULL,
+                                              skb->h.th,
+                                              sk->sk_protocol,
+                                              skb->len);
+       }
+#endif
+
        icsk->icsk_af_ops->send_check(sk, skb->len, skb);
 
        if (likely(tcb->flags & TCPCB_FLAG_ACK))
@@ -476,13 +547,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 
        tcp_enter_cwr(sk);
 
-       /* NET_XMIT_CN is special. It does not guarantee,
-        * that this packet is lost. It tells that device
-        * is about to start to drop packets or already
-        * drops some packets of the same priority and
-        * invokes us to send less aggressively.
-        */
-       return err == NET_XMIT_CN ? 0 : err;
+       return net_xmit_eval(err);
 
 #undef SYSCTL_FLAG_TSTAMPS
 #undef SYSCTL_FLAG_WSCALE
@@ -577,7 +642,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss
        TCP_SKB_CB(buff)->sacked = TCP_SKB_CB(skb)->sacked;
        TCP_SKB_CB(skb)->sacked &= ~TCPCB_AT_TAIL;
 
-       if (!skb_shinfo(skb)->nr_frags && skb->ip_summed != CHECKSUM_HW) {
+       if (!skb_shinfo(skb)->nr_frags && skb->ip_summed != CHECKSUM_PARTIAL) {
                /* Copy and checksum data tail into the new buffer. */
                buff->csum = csum_partial_copy_nocheck(skb->data + len, skb_put(buff, nsize),
                                                       nsize, 0);
@@ -586,7 +651,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss
 
                skb->csum = csum_block_sub(skb->csum, buff->csum, len);
        } else {
-               skb->ip_summed = CHECKSUM_HW;
+               skb->ip_summed = CHECKSUM_PARTIAL;
                skb_split(skb, buff, len);
        }
 
@@ -689,7 +754,7 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
                __pskb_trim_head(skb, len - skb_headlen(skb));
 
        TCP_SKB_CB(skb)->seq += len;
-       skb->ip_summed = CHECKSUM_HW;
+       skb->ip_summed = CHECKSUM_PARTIAL;
 
        skb->truesize        -= len;
        sk->sk_wmem_queued   -= len;
@@ -838,6 +903,11 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
                mss_now -= (TCPOLEN_SACK_BASE_ALIGNED +
                            (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK));
 
+#ifdef CONFIG_TCP_MD5SIG
+       if (tp->af_specific->md5_lookup(sk, sk))
+               mss_now -= TCPOLEN_MD5SIG_ALIGNED;
+#endif
+
        xmit_size_goal = mss_now;
 
        if (doing_tso) {
@@ -858,8 +928,6 @@ unsigned int tcp_current_mss(struct sock *sk, int large_allowed)
        return mss_now;
 }
 
-EXPORT_SYMBOL_GPL(tcp_current_mss);
-
 /* Congestion window validation. (RFC2861) */
 
 static void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)
@@ -875,7 +943,8 @@ static void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)
                if (tp->packets_out > tp->snd_cwnd_used)
                        tp->snd_cwnd_used = tp->packets_out;
 
-               if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= inet_csk(sk)->icsk_rto)
+               if (sysctl_tcp_slow_start_after_idle &&
+                   (s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= inet_csk(sk)->icsk_rto)
                        tcp_cwnd_application_limited(sk);
        }
 }
@@ -897,7 +966,8 @@ static inline unsigned int tcp_cwnd_test(struct tcp_sock *tp, struct sk_buff *sk
        u32 in_flight, cwnd;
 
        /* Don't be strict about the congestion window for the final FIN.  */
-       if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)
+       if ((TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
+           tcp_skb_pcount(skb) == 1)
                return 1;
 
        in_flight = tcp_packets_in_flight(tp);
@@ -1064,7 +1134,7 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
        /* This packet was never sent out yet, so no SACK bits. */
        TCP_SKB_CB(buff)->sacked = 0;
 
-       buff->ip_summed = skb->ip_summed = CHECKSUM_HW;
+       buff->ip_summed = skb->ip_summed = CHECKSUM_PARTIAL;
        skb_split(skb, buff, len);
 
        /* Fix up tso_factor for both original and new SKB.  */
@@ -1089,10 +1159,14 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
        u32 send_win, cong_win, limit, in_flight;
 
        if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)
-               return 0;
+               goto send_now;
 
        if (icsk->icsk_ca_state != TCP_CA_Open)
-               return 0;
+               goto send_now;
+
+       /* Defer for less than two clock ticks. */
+       if (!tp->tso_deferred && ((jiffies<<1)>>1) - (tp->tso_deferred>>1) > 1)
+               goto send_now;
 
        in_flight = tcp_packets_in_flight(tp);
 
@@ -1108,7 +1182,7 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
 
        /* If a full-sized TSO skb can be sent, do it. */
        if (limit >= 65536)
-               return 0;
+               goto send_now;
 
        if (sysctl_tcp_tso_win_divisor) {
                u32 chunk = min(tp->snd_wnd, tp->snd_cwnd * tp->mss_cache);
@@ -1118,7 +1192,7 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
                 */
                chunk /= sysctl_tcp_tso_win_divisor;
                if (limit >= chunk)
-                       return 0;
+                       goto send_now;
        } else {
                /* Different approach, try not to defer past a single
                 * ACK.  Receiver should ACK every other full sized
@@ -1126,11 +1200,17 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
                 * then send now.
                 */
                if (limit > tcp_max_burst(tp) * tp->mss_cache)
-                       return 0;
+                       goto send_now;
        }
 
        /* Ok, it looks like it is advisable to defer.  */
+       tp->tso_deferred = 1 | (jiffies<<1);
+
        return 1;
+
+send_now:
+       tp->tso_deferred = 0;
+       return 0;
 }
 
 /* Create a new MTU probe if we are ready.
@@ -1208,8 +1288,7 @@ static int tcp_mtu_probe(struct sock *sk)
        TCP_SKB_CB(nskb)->flags = TCPCB_FLAG_ACK;
        TCP_SKB_CB(nskb)->sacked = 0;
        nskb->csum = 0;
-       if (skb->ip_summed == CHECKSUM_HW)
-               nskb->ip_summed = CHECKSUM_HW;
+       nskb->ip_summed = skb->ip_summed;
 
        len = 0;
        while (len < probe_size) {
@@ -1233,7 +1312,7 @@ static int tcp_mtu_probe(struct sock *sk)
                                                   ~(TCPCB_FLAG_FIN|TCPCB_FLAG_PSH);
                        if (!skb_shinfo(skb)->nr_frags) {
                                skb_pull(skb, copy);
-                               if (skb->ip_summed != CHECKSUM_HW)
+                               if (skb->ip_summed != CHECKSUM_PARTIAL)
                                        skb->csum = csum_partial(skb->data, skb->len, 0);
                        } else {
                                __pskb_trim_head(skb, copy);
@@ -1373,7 +1452,6 @@ void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
                        tcp_check_probe_timer(sk, tp);
        }
 }
-EXPORT_SYMBOL_GPL(__tcp_push_pending_frames);
 
 /* Send _single_ skb sitting at the send head. This function requires
  * true push pending frames to setup probe timer etc.
@@ -1530,6 +1608,9 @@ u32 __tcp_select_window(struct sock *sk)
                 */
                if (window <= free_space - mss || window > free_space)
                        window = (free_space/mss)*mss;
+               else if (mss == full_space &&
+                        free_space > window + full_space/2)
+                       window = free_space;
        }
 
        return window;
@@ -1575,10 +1656,10 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
 
                memcpy(skb_put(skb, next_skb_size), next_skb->data, next_skb_size);
 
-               if (next_skb->ip_summed == CHECKSUM_HW)
-                       skb->ip_summed = CHECKSUM_HW;
+               if (next_skb->ip_summed == CHECKSUM_PARTIAL)
+                       skb->ip_summed = CHECKSUM_PARTIAL;
 
-               if (skb->ip_summed != CHECKSUM_HW)
+               if (skb->ip_summed != CHECKSUM_PARTIAL)
                        skb->csum = csum_block_add(skb->csum, next_skb->csum, skb_size);
 
                /* Update sequence range on original skb. */
@@ -2026,6 +2107,10 @@ struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
        struct tcphdr *th;
        int tcp_header_size;
        struct sk_buff *skb;
+#ifdef CONFIG_TCP_MD5SIG
+       struct tcp_md5sig_key *md5;
+       __u8 *md5_hash_location;
+#endif
 
        skb = sock_wmalloc(sk, MAX_TCP_HEADER + 15, 1, GFP_ATOMIC);
        if (skb == NULL)
@@ -2041,6 +2126,13 @@ struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
                           (ireq->wscale_ok ? TCPOLEN_WSCALE_ALIGNED : 0) +
                           /* SACK_PERM is in the place of NOP NOP of TS */
                           ((ireq->sack_ok && !ireq->tstamp_ok) ? TCPOLEN_SACKPERM_ALIGNED : 0));
+
+#ifdef CONFIG_TCP_MD5SIG
+       /* Are we doing MD5 on this segment? If so - make room for it */
+       md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req);
+       if (md5)
+               tcp_header_size += TCPOLEN_MD5SIG_ALIGNED;
+#endif
        skb->h.th = th = (struct tcphdr *) skb_push(skb, tcp_header_size);
 
        memset(th, 0, sizeof(struct tcphdr));
@@ -2072,17 +2164,35 @@ struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
        }
 
        /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */
-       th->window = htons(req->rcv_wnd);
+       th->window = htons(min(req->rcv_wnd, 65535U));
 
        TCP_SKB_CB(skb)->when = tcp_time_stamp;
-       tcp_syn_build_options((__u32 *)(th + 1), dst_metric(dst, RTAX_ADVMSS), ireq->tstamp_ok,
+       tcp_syn_build_options((__be32 *)(th + 1), dst_metric(dst, RTAX_ADVMSS), ireq->tstamp_ok,
                              ireq->sack_ok, ireq->wscale_ok, ireq->rcv_wscale,
                              TCP_SKB_CB(skb)->when,
-                             req->ts_recent);
+                             req->ts_recent,
+                             (
+#ifdef CONFIG_TCP_MD5SIG
+                              md5 ? &md5_hash_location :
+#endif
+                              NULL)
+                             );
 
        skb->csum = 0;
        th->doff = (tcp_header_size >> 2);
        TCP_INC_STATS(TCP_MIB_OUTSEGS);
+
+#ifdef CONFIG_TCP_MD5SIG
+       /* Okay, we have all we need - do the md5 hash if needed */
+       if (md5) {
+               tp->af_specific->calc_md5_hash(md5_hash_location,
+                                              md5,
+                                              NULL, dst, req,
+                                              skb->h.th, sk->sk_protocol,
+                                              skb->len);
+       }
+#endif
+
        return skb;
 }
 
@@ -2101,6 +2211,11 @@ static void tcp_connect_init(struct sock *sk)
        tp->tcp_header_len = sizeof(struct tcphdr) +
                (sysctl_tcp_timestamps ? TCPOLEN_TSTAMP_ALIGNED : 0);
 
+#ifdef CONFIG_TCP_MD5SIG
+       if (tp->af_specific->md5_lookup(sk, sk) != NULL)
+               tp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED;
+#endif
+
        /* If user gave his TCP_MAXSEG, record it to clamp */
        if (tp->rx_opt.user_mss)
                tp->rx_opt.mss_clamp = tp->rx_opt.user_mss;