aboutsummaryrefslogtreecommitdiffstats
path: root/src/vnet/tcp/tcp_output.c
diff options
context:
space:
mode:
authorFlorin Coras <fcoras@cisco.com>2017-05-04 14:25:50 -0700
committerDave Barach <openvpp@barachs.net>2017-05-07 12:38:39 +0000
commitc8343412ee0deaa8e9192cbc4846aae1e9f48a4d (patch)
treeabcf3611fe398e7744dc9c9bdb080a1453caa9e4 /src/vnet/tcp/tcp_output.c
parent3af90fceb61d0c236709c25df936bbbf304cbff5 (diff)
Include TCP options in segment size computation
Ensure that TCP data plus options does not exceed peer's advertised MSS. Change-Id: I0de824cb3619346f0394dd694942fc1cf33a82b7 Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/vnet/tcp/tcp_output.c')
-rw-r--r--src/vnet/tcp/tcp_output.c104
1 files changed, 69 insertions, 35 deletions
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 7ee930c61af..2a1b140750c 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -64,26 +64,6 @@ format_tcp_tx_trace (u8 * s, va_list * args)
return s;
}
-void
-tcp_set_snd_mss (tcp_connection_t * tc)
-{
- u16 snd_mss;
-
- /* TODO find our iface MTU */
- snd_mss = dummy_mtu;
-
- /* TODO cache mss and consider PMTU discovery */
- snd_mss = clib_min (tc->opt.mss, snd_mss);
-
- tc->snd_mss = snd_mss;
-
- if (tc->snd_mss == 0)
- {
- clib_warning ("snd mss is 0");
- tc->snd_mss = dummy_mtu;
- }
-}
-
static u8
tcp_window_compute_scale (u32 available_space)
{
@@ -100,7 +80,7 @@ tcp_window_compute_scale (u32 available_space)
always_inline u32
tcp_initial_wnd_unscaled (tcp_connection_t * tc)
{
- return TCP_IW_N_SEGMENTS * dummy_mtu;
+ return TCP_IW_N_SEGMENTS * tc->mss;
}
/**
@@ -310,7 +290,7 @@ tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts)
u8 len = 0;
opts->flags |= TCP_OPTS_FLAG_MSS;
- opts->mss = dummy_mtu; /*XXX discover that */
+ opts->mss = tc->mss;
len += TCP_OPTION_LEN_MSS;
if (tcp_opts_wscale (&tc->opt))
@@ -389,6 +369,57 @@ tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts,
}
}
+/**
+ * Update max segment size we're able to process.
+ *
+ * The value is constrained by our interface's MTU and IP options. It is
+ * also what we advertise to our peer.
+ */
+void
+tcp_update_rcv_mss (tcp_connection_t * tc)
+{
+ /* TODO find our iface MTU */
+ tc->mss = dummy_mtu;
+}
+
+/**
+ * Update snd_mss to reflect the effective segment size that we can send
+ * by taking into account all TCP options, including SACKs
+ */
+void
+tcp_update_snd_mss (tcp_connection_t * tc)
+{
+ /* Compute options to be used for connection. These may be reused when
+ * sending data or to compute the effective mss (snd_mss) */
+ tc->snd_opts_len =
+ tcp_make_options (tc, &tc->snd_opts, TCP_STATE_ESTABLISHED);
+
+ /* XXX check if MTU has been updated */
+ tc->snd_mss = clib_min (tc->mss, tc->opt.mss) - tc->snd_opts_len;
+}
+
+void
+tcp_init_mss (tcp_connection_t * tc)
+{
+ tcp_update_rcv_mss (tc);
+
+ /* TODO cache mss and consider PMTU discovery */
+ tc->snd_mss = clib_min (tc->opt.mss, tc->mss);
+
+ if (tc->snd_mss == 0)
+ {
+ clib_warning ("snd mss is 0");
+ tc->snd_mss = tc->mss;
+ }
+
+ /* We should have enough space for 40 bytes of options */
+ ASSERT (tc->snd_mss > 45);
+
+ /* If we use timestamp option, account for it */
+ if (tcp_opts_tstamp (&tc->opt))
+ tc->snd_mss -= TCP_OPTION_LEN_TIMESTAMP;
+}
+
#define tcp_get_free_buffer_index(tm, bidx) \
do { \
u32 *my_tx_buffers, n_free_buffers; \
@@ -886,20 +917,20 @@ tcp_make_state_flags (tcp_state_t next_state)
*/
static void
tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
- tcp_state_t next_state)
+ tcp_state_t next_state, u8 compute_opts)
{
u32 advertise_wnd, data_len;
- u8 tcp_opts_len, tcp_hdr_opts_len, opts_write_len, flags;
- tcp_options_t _snd_opts, *snd_opts = &_snd_opts;
+ u8 tcp_hdr_opts_len, opts_write_len, flags;
tcp_header_t *th;
data_len = b->current_length;
vnet_buffer (b)->tcp.flags = 0;
- /* Make and write options */
- memset (snd_opts, 0, sizeof (*snd_opts));
- tcp_opts_len = tcp_make_options (tc, snd_opts, next_state);
- tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t);
+ if (compute_opts)
+ tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
+
+ /* Write pre-computed options */
+ tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t);
/* Get rcv window to advertise */
advertise_wnd = tcp_window_to_advertise (tc, next_state);
@@ -910,9 +941,9 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
tc->rcv_nxt, tcp_hdr_opts_len, flags,
advertise_wnd);
- opts_write_len = tcp_options_write ((u8 *) (th + 1), snd_opts);
+ opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
- ASSERT (opts_write_len == tcp_opts_len);
+ ASSERT (opts_write_len == tc->snd_opts_len);
/* Tag the buffer with the connection index */
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
@@ -993,6 +1024,8 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b,
goto done;
}
+ tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
+
ASSERT (max_bytes <= tc->snd_mss);
n_bytes = stream_session_peek_bytes (&tc->connection,
@@ -1000,7 +1033,7 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b,
max_bytes);
ASSERT (n_bytes != 0);
b->current_length = n_bytes;
- tcp_push_hdr_i (tc, b, tc->state);
+ tcp_push_hdr_i (tc, b, tc->state, 0);
tc->rtx_bytes += n_bytes;
done:
@@ -1097,7 +1130,7 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
vlib_buffer_make_headroom (b, MAX_HDRS_LEN);
- tcp_push_hdr_i (tc, b, tc->state);
+ tcp_push_hdr_i (tc, b, tc->state, 1);
/* Account for the SYN */
tc->snd_nxt += 1;
@@ -1168,6 +1201,7 @@ tcp_timer_persist_handler (u32 index)
/* Try to force the first unsent segment */
tcp_get_free_buffer_index (tm, &bi);
b = vlib_get_buffer (vm, bi);
+ tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state);
n_bytes = stream_session_peek_bytes (&tc->connection,
vlib_buffer_get_current (b),
tc->snd_una_max - tc->snd_una,
@@ -1180,7 +1214,7 @@ tcp_timer_persist_handler (u32 index)
}
b->current_length = n_bytes;
- tcp_push_hdr_i (tc, b, tc->state);
+ tcp_push_hdr_i (tc, b, tc->state, 0);
tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
/* Re-enable persist timer */
@@ -1507,7 +1541,7 @@ tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
tcp_connection_t *tc;
tc = (tcp_connection_t *) tconn;
- tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED);
+ tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0);
return 0;
}