In order to reduce memory and code footprint, we merge the array
for l2 flag frames into the one for payload frames.
This change also ensures that no flag message will be sent out
over the l2 media bypassing already queued payload messages.
Signed-off-by: Jon Maloy <jmaloy(a)redhat.com>
---
tcp.c | 3 +--
tcp_buf.c | 70 ++++++++++++-------------------------------------------
2 files changed, 16 insertions(+), 57 deletions(-)
diff --git a/tcp.c b/tcp.c
index 12e864f..dd060d0 100644
--- a/tcp.c
+++ b/tcp.c
@@ -868,7 +868,6 @@ bool tcp_flow_defer(const struct tcp_tap_conn *conn)
/* cppcheck-suppress [constParameterPointer, unmatchedSuppression] */
void tcp_defer_handler(struct ctx *c)
{
- tcp_flags_flush(c);
tcp_payload_flush(c);
}
@@ -1148,7 +1147,7 @@ static void tcp_update_seqack_from_tap(const struct ctx *c,
* 1 otherwise
*/
int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn,
- int flags, struct tcphdr *th, char *data,
+ int flags, struct tcphdr *th, uint8_t *data,
size_t *optlen)
{
struct tcp_info tinfo = { 0 };
diff --git a/tcp_buf.c b/tcp_buf.c
index 625c29c..58636d1 100644
--- a/tcp_buf.c
+++ b/tcp_buf.c
@@ -33,6 +33,7 @@
#include "tcp_internal.h"
#include "tcp_buf.h"
+#define PAYLOAD_FLAGS htons(0x5010) /* doff = 5, ack = 1 */
#define TCP_FRAMES_MEM 128
#define TCP_FRAMES \
(c->mode == MODE_PASTA ? 1 : TCP_FRAMES_MEM)
@@ -52,21 +53,6 @@ struct tcp_payload_t {
} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
#endif
-/**
- * struct tcp_flags_t - TCP header and data to send zero-length
- * segments (flags)
- * @th: TCP header
- * @opts TCP options
- */
-struct tcp_flags_t {
- struct tcphdr th;
- char opts[OPT_MSS_LEN + OPT_WS_LEN + 1];
-#ifdef __AVX2__
-} __attribute__ ((packed, aligned(32)));
-#else
-} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
-#endif
-
/* Ethernet header for IPv4 and IPv6 frames */
static struct ethhdr tcp4_eth_src;
static struct ethhdr tcp6_eth_src;
@@ -87,22 +73,10 @@ static_assert(MSS6 <= sizeof(tcp_payload[0].data), "MSS6 is
greater than 65516")
static struct tcp_tap_conn *tcp_frame_conns[TCP_FRAMES_MEM];
static unsigned int tcp_payload_used;
-static struct tap_hdr tcp_flags_tap_hdr[TCP_FRAMES_MEM];
-/* IPv4 headers for TCP segment without payload */
-static struct iphdr tcp4_flags_ip[TCP_FRAMES_MEM];
-/* TCP segments without payload for IPv4 frames */
-static struct tcp_flags_t tcp_flags[TCP_FRAMES_MEM];
-
-static unsigned int tcp_flags_used;
-
-/* IPv6 headers for TCP segment without payload */
-static struct ipv6hdr tcp6_flags_ip[TCP_FRAMES_MEM];
-
/* recvmsg()/sendmsg() data for tap */
static struct iovec iov_sock [TCP_FRAMES_MEM + 1];
static struct iovec tcp_l2_iov[TCP_FRAMES_MEM][TCP_NUM_IOVS];
-static struct iovec tcp_l2_flags_iov[TCP_FRAMES_MEM][TCP_NUM_IOVS];
/**
* tcp_update_l2_buf() - Update Ethernet header buffers with addresses
@@ -135,13 +109,6 @@ void tcp_sock_iov_init(const struct ctx *c)
tcp_payload[i].th.ack = 1;
}
- for (i = 0; i < ARRAY_SIZE(tcp_flags); i++) {
- tcp6_flags_ip[i] = ip6;
- tcp4_flags_ip[i] = iph;
- tcp_flags[i].th.doff = sizeof(struct tcphdr) / 4;
- tcp_flags[i].th.ack = 1;
- }
-
for (i = 0; i < TCP_FRAMES_MEM; i++) {
struct iovec *iov = tcp_l2_iov[i];
@@ -149,14 +116,6 @@ void tcp_sock_iov_init(const struct ctx *c)
iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr);
iov[TCP_IOV_PAYLOAD].iov_base = &tcp_payload[i];
}
-
- for (i = 0; i < TCP_FRAMES_MEM; i++) {
- struct iovec *iov = tcp_l2_flags_iov[i];
-
- iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp_flags_tap_hdr[i]);
- iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr);
- iov[TCP_IOV_PAYLOAD].iov_base = &tcp_flags[i];
- }
}
/**
@@ -165,9 +124,7 @@ void tcp_sock_iov_init(const struct ctx *c)
*/
void tcp_flags_flush(const struct ctx *c)
{
- tap_send_frames(c, &tcp_l2_flags_iov[0][0], TCP_NUM_IOVS,
- tcp_flags_used);
- tcp_flags_used = 0;
+ tcp_payload_flush(c);
}
/**
@@ -225,37 +182,35 @@ void tcp_payload_flush(const struct ctx *c)
*/
int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
{
- struct tcp_flags_t *payload;
+ struct tcp_payload_t *payload;
struct iovec *iov;
size_t optlen;
size_t l4len;
uint32_t seq;
int ret;
- iov = tcp_l2_flags_iov[tcp_flags_used];
+ iov = tcp_l2_iov[tcp_payload_used];
if (CONN_V4(conn)) {
- iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_flags_ip[tcp_flags_used]);
+ iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[tcp_payload_used]);
iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
} else {
- iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_flags_ip[tcp_flags_used]);
+ iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[tcp_payload_used]);
iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
}
payload = iov[TCP_IOV_PAYLOAD].iov_base;
seq = conn->seq_to_tap;
ret = tcp_prepare_flags(c, conn, flags, &payload->th,
- payload->opts, &optlen);
+ payload->data, &optlen);
if (ret <= 0)
return ret;
- tcp_flags_used++;
+ tcp_payload_used++;
l4len = tcp_l2_buf_fill_headers(conn, iov, optlen, NULL, seq, false);
iov[TCP_IOV_PAYLOAD].iov_len = l4len;
-
if (flags & DUP_ACK) {
- struct iovec *dup_iov;
+ struct iovec *dup_iov = tcp_l2_iov[tcp_payload_used++];
- dup_iov = tcp_l2_flags_iov[tcp_flags_used++];
memcpy(dup_iov[TCP_IOV_TAP].iov_base, iov[TCP_IOV_TAP].iov_base,
iov[TCP_IOV_TAP].iov_len);
dup_iov[TCP_IOV_ETH].iov_base = iov[TCP_IOV_ETH].iov_base;
@@ -265,7 +220,7 @@ int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn,
int flags)
dup_iov[TCP_IOV_PAYLOAD].iov_len = l4len;
}
- if (tcp_flags_used > TCP_FRAMES_MEM - 2)
+ if (tcp_payload_used > TCP_FRAMES_MEM - 2)
tcp_flags_flush(c);
return 0;
@@ -282,8 +237,10 @@ int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn,
int flags)
static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn,
ssize_t dlen, int no_csum, uint32_t seq)
{
+ struct tcp_payload_t *payload;
const uint16_t *check = NULL;
struct iovec *iov;
+ uint16_t *flags;
size_t l4len;
conn->seq_to_tap = seq + dlen;
@@ -302,6 +259,9 @@ static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn
*conn,
iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[tcp_payload_used]);
iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
}
+ payload = iov[TCP_IOV_PAYLOAD].iov_base;
+ flags = &payload->th.window - 1;
+ *(flags) = PAYLOAD_FLAGS;
l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, check, seq, false);
iov[TCP_IOV_PAYLOAD].iov_len = l4len;
if (++tcp_payload_used > TCP_FRAMES_MEM - 1)
--
2.45.2