From 02833ff3294f4abbd8e3d52b38446e0f8f533ffc Mon Sep 17 00:00:00 2001
From: Srikanth A <srakula@cisco.com>
Date: Wed, 2 Oct 2019 17:48:58 -0700
Subject: tcp: custom checksum calculations for Ipv4/Ipv6
Type: feature
Based on the configuration, we can disable checksum offload capability
and calculate checksum while pushing the TCP & IP header.
This saves some cycles when VPP stack is used in legacy hardware devices.
Signed-off-by: Srikanth A <srakula@cisco.com>
Change-Id: Ic1b3fcf3040917e47ee65263694ebf7437ac5668
(cherry picked from commit 3642782a2748503f5b5ccf89d1575c1d489948ef)
---
src/vnet/ip/ip.h | 79 +++++++++++++++++++++++++++++++
src/vnet/ip/ip4_forward.c | 46 ++----------------
src/vnet/ip/ip6.h | 3 +-
src/vnet/ip/ip6_forward.c | 69 ++++++---------------------
src/vnet/tcp/tcp.h | 3 ++
src/vnet/tcp/tcp_output.c | 116 +++++++++++++++++++++++++++++++++++++---------
6 files changed, 194 insertions(+), 122 deletions(-)
(limited to 'src')
diff --git a/src/vnet/ip/ip.h b/src/vnet/ip/ip.h
index 7a82dcf8f2b..65ccaef40c2 100644
--- a/src/vnet/ip/ip.h
+++ b/src/vnet/ip/ip.h
@@ -195,6 +195,85 @@ ip_incremental_checksum_buffer (vlib_main_t * vm,
return sum;
}
+always_inline u16
+ip_calculate_l4_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
+ ip_csum_t sum0, u32 payload_length,
+ u8 * iph, u32 ip_header_size, u8 * l4h)
+{
+ u16 sum16;
+ u8 *data_this_buffer, length_odd;
+ u32 n_bytes_left, n_this_buffer, n_ip_bytes_this_buffer;
+
+ n_bytes_left = payload_length;
+
+ if (l4h) /* packet l4 header and no buffer chain involved */
+ {
+ ASSERT (p0 == NULL);
+ n_this_buffer = payload_length;
+ data_this_buffer = l4h;
+ }
+ else
+ {
+ ASSERT (p0);
+ if (iph) /* ip header pointer set to packet in buffer */
+ {
+ ASSERT (ip_header_size);
+ n_this_buffer = payload_length;
+ data_this_buffer = iph + ip_header_size; /* at l4 header */
+ n_ip_bytes_this_buffer =
+ p0->current_length - (((u8 *) iph - p0->data) - p0->current_data);
+ if (PREDICT_FALSE (payload_length + ip_header_size >
+ n_ip_bytes_this_buffer))
+ {
+ n_this_buffer = n_ip_bytes_this_buffer - ip_header_size;
+ if (PREDICT_FALSE (n_this_buffer >> 31))
+ { /* error - ip header don't fit this buffer */
+ ASSERT (0);
+ return 0xfefe;
+ }
+ }
+ }
+ else /* packet in buffer with no ip header */
+ { /* buffer current pointer at l4 header */
+ n_this_buffer = p0->current_length;
+ data_this_buffer = vlib_buffer_get_current (p0);
+ }
+ n_this_buffer = clib_min (n_this_buffer, n_bytes_left);
+ }
+
+ while (1)
+ {
+ sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
+ n_bytes_left -= n_this_buffer;
+ if (n_bytes_left == 0)
+ break;
+
+ if (!(p0->flags & VLIB_BUFFER_NEXT_PRESENT))
+ {
+ ASSERT (0); /* error - more buffer expected */
+ return 0xfefe;
+ }
+
+ length_odd = (n_this_buffer & 1);
+
+ p0 = vlib_get_buffer (vm, p0->next_buffer);
+ data_this_buffer = vlib_buffer_get_current (p0);
+ n_this_buffer = clib_min (p0->current_length, n_bytes_left);
+
+ if (PREDICT_FALSE (length_odd))
+ {
+ /* Prepend a 0 byte to maintain 2-byte checksum alignment */
+ data_this_buffer--;
+ n_this_buffer++;
+ n_bytes_left++;
+ data_this_buffer[0] = 0;
+ }
+ }
+
+ sum16 = ~ip_csum_fold (sum0);
+ return sum16;
+}
+
void ip_del_all_interface_addresses (vlib_main_t * vm, u32 sw_if_index);
extern vlib_node_registration_t ip4_inacl_node;
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index d4717c6db4b..40c396c4f3b 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -1303,10 +1303,6 @@ ip4_tcp_udp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
{
ip_csum_t sum0;
u32 ip_header_length, payload_length_host_byte_order;
- u32 n_this_buffer, n_bytes_left, n_ip_bytes_this_buffer;
- u16 sum16;
- u8 *data_this_buffer;
- u8 length_odd;
/* Initialize checksum with ip header. */
ip_header_length = ip4_header_bytes (ip0);
@@ -1329,45 +1325,9 @@ ip4_tcp_udp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
sum0 =
ip_csum_with_carry (sum0, clib_mem_unaligned (&ip0->src_address, u64));
- n_bytes_left = n_this_buffer = payload_length_host_byte_order;
- data_this_buffer = (u8 *) ip0 + ip_header_length;
- n_ip_bytes_this_buffer =
- p0->current_length - (((u8 *) ip0 - p0->data) - p0->current_data);
- if (n_this_buffer + ip_header_length > n_ip_bytes_this_buffer)
- {
- n_this_buffer = n_ip_bytes_this_buffer > ip_header_length ?
- n_ip_bytes_this_buffer - ip_header_length : 0;
- }
-
- while (1)
- {
- sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
- n_bytes_left -= n_this_buffer;
- if (n_bytes_left == 0)
- break;
-
- ASSERT (p0->flags & VLIB_BUFFER_NEXT_PRESENT);
- if (!(p0->flags & VLIB_BUFFER_NEXT_PRESENT))
- return 0xfefe;
-
- length_odd = (n_this_buffer & 1);
-
- p0 = vlib_get_buffer (vm, p0->next_buffer);
- data_this_buffer = vlib_buffer_get_current (p0);
- n_this_buffer = clib_min (p0->current_length, n_bytes_left);
-
- if (PREDICT_FALSE (length_odd))
- {
- /* Prepend a 0 or the resulting checksum will be incorrect. */
- data_this_buffer--;
- n_this_buffer++;
- n_bytes_left++;
- data_this_buffer[0] = 0;
- }
- }
-
- sum16 = ~ip_csum_fold (sum0);
- return sum16;
+ return ip_calculate_l4_checksum (vm, p0, sum0,
+ payload_length_host_byte_order, (u8 *) ip0,
+ ip_header_length, NULL);
}
u32
diff --git a/src/vnet/ip/ip6.h b/src/vnet/ip/ip6.h
index 810fd70ff0c..94c5080a0aa 100644
--- a/src/vnet/ip/ip6.h
+++ b/src/vnet/ip/ip6.h
@@ -683,7 +683,8 @@ vlib_buffer_push_ip6 (vlib_main_t * vm, vlib_buffer_t * b,
sizeof (ip6h->src_address));
clib_memcpy_fast (ip6h->dst_address.as_u8, dst->as_u8,
sizeof (ip6h->src_address));
- b->flags |= VNET_BUFFER_F_IS_IP6;
+ vnet_buffer (b)->l3_hdr_offset = (u8 *) ip6h - b->data;
+ b->flags |= VNET_BUFFER_F_IS_IP6 | VNET_BUFFER_F_L3_HDR_OFFSET_VALID;
return ip6h;
}
diff --git a/src/vnet/ip/ip6_forward.c b/src/vnet/ip/ip6_forward.c
index ea13116d8aa..47fb57ae201 100644
--- a/src/vnet/ip/ip6_forward.c
+++ b/src/vnet/ip/ip6_forward.c
@@ -1011,11 +1011,10 @@ ip6_tcp_udp_icmp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
ip6_header_t * ip0, int *bogus_lengthp)
{
ip_csum_t sum0;
- u16 sum16, payload_length_host_byte_order;
- u32 i, n_this_buffer, n_bytes_left;
+ u16 payload_length_host_byte_order;
+ u32 i;
u32 headers_size = sizeof (ip0[0]);
u8 *data_this_buffer;
- u8 length_odd;
ASSERT (bogus_lengthp);
*bogus_lengthp = 0;
@@ -1027,14 +1026,10 @@ ip6_tcp_udp_icmp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
for (i = 0; i < ARRAY_LEN (ip0->src_address.as_uword); i++)
{
- sum0 = ip_csum_with_carry (sum0,
- clib_mem_unaligned (&ip0->
- src_address.as_uword[i],
- uword));
- sum0 =
- ip_csum_with_carry (sum0,
- clib_mem_unaligned (&ip0->dst_address.as_uword[i],
- uword));
+ sum0 = ip_csum_with_carry
+ (sum0, clib_mem_unaligned (&ip0->src_address.as_uword[i], uword));
+ sum0 = ip_csum_with_carry
+ (sum0, clib_mem_unaligned (&ip0->dst_address.as_uword[i], uword));
}
/* some icmp packets may come with a "router alert" hop-by-hop extension header (e.g., mldv2 packets)
@@ -1056,52 +1051,14 @@ ip6_tcp_udp_icmp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
headers_size += skip_bytes;
}
- n_bytes_left = n_this_buffer = payload_length_host_byte_order;
-
if (p0)
- {
- u32 n_ip_bytes_this_buffer =
- p0->current_length - (((u8 *) ip0 - p0->data) - p0->current_data);
- if (n_this_buffer + headers_size > n_ip_bytes_this_buffer)
- {
- n_this_buffer = p0->current_length > headers_size ?
- n_ip_bytes_this_buffer - headers_size : 0;
- }
- }
-
- while (1)
- {
- sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
- n_bytes_left -= n_this_buffer;
- if (n_bytes_left == 0)
- break;
-
- ASSERT (p0->flags & VLIB_BUFFER_NEXT_PRESENT);
- if (!(p0->flags & VLIB_BUFFER_NEXT_PRESENT))
- {
- *bogus_lengthp = 1;
- return 0xfefe;
- }
-
- length_odd = (n_this_buffer & 1);
-
- p0 = vlib_get_buffer (vm, p0->next_buffer);
- data_this_buffer = vlib_buffer_get_current (p0);
- n_this_buffer = clib_min (p0->current_length, n_bytes_left);
-
- if (PREDICT_FALSE (length_odd))
- {
- /* Prepend a 0 or the resulting checksum will be incorrect. */
- data_this_buffer--;
- n_this_buffer++;
- n_bytes_left++;
- data_this_buffer[0] = 0;
- }
- }
-
- sum16 = ~ip_csum_fold (sum0);
-
- return sum16;
+ return ip_calculate_l4_checksum (vm, p0, sum0,
+ payload_length_host_byte_order,
+ (u8 *) ip0, headers_size, NULL);
+ else
+ return ip_calculate_l4_checksum (vm, 0, sum0,
+ payload_length_host_byte_order, NULL, 0,
+ data_this_buffer);
}
u32
diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index a1b7d4cbd0d..1bf32818171 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -120,6 +120,7 @@ extern timer_expiration_handler tcp_timer_retransmit_syn_handler;
_(RATE_SAMPLE, "Conn does rate sampling") \
_(TRACK_BURST, "Track burst") \
_(ZERO_RWND_SENT, "Zero RWND sent") \
+ _(NO_CSUM_OFFLOAD, "No Checksum Offload") \
typedef enum _tcp_connection_flag_bits
{
@@ -1233,6 +1234,8 @@ vlib_buffer_push_tcp_net_order (vlib_buffer_t * b, u16 sp, u16 dp, u32 seq,
th->window = wnd;
th->checksum = 0;
th->urgent_pointer = 0;
+ vnet_buffer (b)->l4_hdr_offset = (u8 *) th - b->data;
+ b->flags |= VNET_BUFFER_F_L4_HDR_OFFSET_VALID;
return th;
}
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 7ebea37fc43..a7b0e398d36 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -444,6 +444,78 @@ tcp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b)
return vlib_buffer_make_headroom (b, TRANSPORT_MAX_HDRS_LEN);
}
+
+/* Compute TCP checksum in software when offloading is disabled for a connection */
+u16
+ip6_tcp_compute_checksum_custom (vlib_main_t * vm, vlib_buffer_t * p0,
+ ip46_address_t * src, ip46_address_t * dst)
+{
+ ip_csum_t sum0;
+ u16 payload_length_host_byte_order;
+ u32 i;
+
+ /* Initialize checksum with ip header. */
+ sum0 = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, p0)) +
+ clib_host_to_net_u16 (IP_PROTOCOL_TCP);
+ payload_length_host_byte_order = vlib_buffer_length_in_chain (vm, p0);
+
+ for (i = 0; i < ARRAY_LEN (src->ip6.as_uword); i++)
+ {
+ sum0 = ip_csum_with_carry
+ (sum0, clib_mem_unaligned (&src->ip6.as_uword[i], uword));
+ sum0 = ip_csum_with_carry
+ (sum0, clib_mem_unaligned (&dst->ip6.as_uword[i], uword));
+ }
+
+ return ip_calculate_l4_checksum (vm, p0, sum0,
+ payload_length_host_byte_order, NULL, 0,
+ NULL);
+}
+
+u16
+ip4_tcp_compute_checksum_custom (vlib_main_t * vm, vlib_buffer_t * p0,
+ ip46_address_t * src, ip46_address_t * dst)
+{
+ ip_csum_t sum0;
+ u32 payload_length_host_byte_order;
+
+ payload_length_host_byte_order = vlib_buffer_length_in_chain (vm, p0);
+ sum0 =
+ clib_host_to_net_u32 (payload_length_host_byte_order +
+ (IP_PROTOCOL_TCP << 16));
+
+ sum0 = ip_csum_with_carry (sum0, clib_mem_unaligned (&src->ip4, u32));
+ sum0 = ip_csum_with_carry (sum0, clib_mem_unaligned (&dst->ip4, u32));
+
+ return ip_calculate_l4_checksum (vm, p0, sum0,
+ payload_length_host_byte_order, NULL, 0,
+ NULL);
+}
+
+static inline u16
+tcp_compute_checksum (tcp_connection_t * tc, vlib_buffer_t * b)
+{
+ u16 checksum = 0;
+ if (PREDICT_FALSE (tc->flags & TCP_CONN_NO_CSUM_OFFLOAD))
+ {
+ tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
+ vlib_main_t *vm = wrk->vm;
+
+ if (tc->c_is_ip4)
+ checksum = ip4_tcp_compute_checksum_custom
+ (vm, b, &tc->c_lcl_ip, &tc->c_rmt_ip);
+ else
+ checksum = ip6_tcp_compute_checksum_custom
+ (vm, b, &tc->c_lcl_ip, &tc->c_rmt_ip);
+ }
+ else
+ {
+ b->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
+ }
+ return checksum;
+}
+
+
/**
* Prepare ACK
*/
@@ -466,6 +538,9 @@ tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd);
tcp_options_write ((u8 *) (th + 1), snd_opts);
+
+ th->checksum = tcp_compute_checksum (tc, b);
+
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
if (wnd == 0)
@@ -517,6 +592,7 @@ tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b)
initial_wnd);
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
tcp_options_write ((u8 *) (th + 1), &snd_opts);
+ th->checksum = tcp_compute_checksum (tc, b);
}
/**
@@ -541,6 +617,7 @@ tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
tcp_options_write ((u8 *) (th + 1), snd_opts);
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
+ th->checksum = tcp_compute_checksum (tc, b);
}
always_inline void
@@ -786,7 +863,8 @@ tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt,
{
ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
- &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
+ &pkt_ih4->src_address, IP_PROTOCOL_TCP,
+ (!(tc->flags & TCP_CONN_NO_CSUM_OFFLOAD)));
th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
}
else
@@ -833,6 +911,7 @@ tcp_send_reset (tcp_connection_t * tc)
tc->rcv_nxt, tcp_hdr_opts_len, flags,
advertise_wnd);
opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts);
+ th->checksum = tcp_compute_checksum (tc, b);
ASSERT (opts_write_len == tc->snd_opts_len);
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
@@ -851,7 +930,8 @@ tcp_push_ip_hdr (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
{
ip4_header_t *ih;
ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
- &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
+ &tc->c_rmt_ip4, IP_PROTOCOL_TCP,
+ (!(tc->flags & TCP_CONN_NO_CSUM_OFFLOAD)));
th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
}
else
@@ -1082,6 +1162,9 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b, u32 snd_nxt,
tc->bytes_out += data_len;
tc->data_segs_out += 1;
+
+ th->checksum = tcp_compute_checksum (tc, b);
+
TCP_EVT (TCP_EVT_PKTIZE, tc);
}
@@ -2160,30 +2243,19 @@ always_inline void
tcp_output_push_ip (vlib_main_t * vm, vlib_buffer_t * b0,
tcp_connection_t * tc0, u8 is_ip4)
{
- tcp_header_t *th0 = 0;
+ u8 __clib_unused *ih0;
+ tcp_header_t __clib_unused *th0 = vlib_buffer_get_current (b0);
- th0 = vlib_buffer_get_current (b0);
TCP_EVT (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length);
+
if (is_ip4)
- {
- vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
- IP_PROTOCOL_TCP, 1);
- b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
- vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
- th0->checksum = 0;
- }
+ ih0 = vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
+ IP_PROTOCOL_TCP,
+ (!(tc0->flags & TCP_CONN_NO_CSUM_OFFLOAD)));
else
- {
- ip6_header_t *ih0;
- ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6,
- &tc0->c_rmt_ip6, IP_PROTOCOL_TCP);
- b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
- vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
- vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
- b0->flags |=
- VNET_BUFFER_F_L3_HDR_OFFSET_VALID | VNET_BUFFER_F_L4_HDR_OFFSET_VALID;
- th0->checksum = 0;
- }
+ ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6, &tc0->c_rmt_ip6,
+ IP_PROTOCOL_TCP);
+
}
always_inline void
--
cgit