From: David Gibson <david@gibson.dropbear.id.au>
To: Stefano Brivio <sbrivio@redhat.com>, passt-dev@passt.top
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v3 12/18] tcp: Consolidate calculation of total frame size
Date: Fri, 6 Jan 2023 11:43:16 +1100 [thread overview]
Message-ID: <20230106004322.985665-13-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20230106004322.985665-1-david@gibson.dropbear.id.au>
tcp_l2_buf_fill_headers() returns the size of the generated frame including
the ethernet header. The caller then adds on the size of the vnet_len
field to get the total frame size to be passed to the tap device.
Outside the tap code, though, we never care about the ethernet header size
only the final total size we need to put into an iovec. So, consolidate
the total frame size calculation within tcp_l2_buf_fill_headers().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
tcp.c | 35 ++++++++++++++++-------------------
1 file changed, 16 insertions(+), 19 deletions(-)
diff --git a/tcp.c b/tcp.c
index 0920c2a..8bcb039 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1447,7 +1447,7 @@ void tcp_defer_handler(struct ctx *c)
* @check: Checksum, if already known
* @seq: Sequence number for this segment
*
- * Return: 802.3 length, host order
+ * Return: frame length including L2 headers, host order
*/
static size_t tcp_l2_buf_fill_headers(const struct ctx *c,
const struct tcp_tap_conn *conn,
@@ -1455,7 +1455,7 @@ static size_t tcp_l2_buf_fill_headers(const struct ctx *c,
const uint16_t *check, uint32_t seq)
{
const struct in_addr *a4 = inany_v4(&conn->addr);
- size_t ip_len, eth_len;
+ size_t ip_len, tlen;
#define SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq) \
do { \
@@ -1489,9 +1489,10 @@ do { \
tcp_update_check_tcp4(b);
- eth_len = ip_len + sizeof(struct ethhdr);
+ tlen = ip_len + sizeof(struct ethhdr);
if (c->mode == MODE_PASST)
- b->vnet_len = htonl(eth_len);
+ b->vnet_len = htonl(tlen);
+ tlen += sizeof(b->vnet_len);
} else {
struct tcp6_l2_buf_t *b = (struct tcp6_l2_buf_t *)p;
@@ -1514,14 +1515,14 @@ do { \
b->ip6h.flow_lbl[1] = (conn->sock >> 8) & 0xff;
b->ip6h.flow_lbl[2] = (conn->sock >> 0) & 0xff;
- eth_len = ip_len + sizeof(struct ethhdr);
+ tlen = ip_len + sizeof(struct ethhdr);
if (c->mode == MODE_PASST)
- b->vnet_len = htonl(eth_len);
+ b->vnet_len = htonl(tlen);
+ tlen += sizeof(b->vnet_len);
}
-
#undef SET_TCP_HEADER_COMMON_V4_V6
- return eth_len;
+ return tlen;
}
/**
@@ -1627,8 +1628,8 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
struct tcp6_l2_flags_buf_t *b6 = NULL;
struct tcp_info tinfo = { 0 };
socklen_t sl = sizeof(tinfo);
- size_t optlen = 0, eth_len;
int s = conn->sock;
+ size_t optlen = 0;
struct iovec *iov;
struct tcphdr *th;
char *data;
@@ -1717,9 +1718,8 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
th->syn = !!(flags & SYN);
th->fin = !!(flags & FIN);
- eth_len = tcp_l2_buf_fill_headers(c, conn, p, optlen,
- NULL, conn->seq_to_tap);
- iov->iov_len = eth_len + sizeof(uint32_t);
+ iov->iov_len = tcp_l2_buf_fill_headers(c, conn, p, optlen,
+ NULL, conn->seq_to_tap);
if (th->ack)
conn_flag(c, conn, ~ACK_TO_TAP_DUE);
@@ -2079,25 +2079,22 @@ static void tcp_data_to_tap(struct ctx *c, struct tcp_tap_conn *conn,
ssize_t plen, int no_csum, uint32_t seq)
{
struct iovec *iov;
- size_t len;
if (CONN_V4(conn)) {
struct tcp4_l2_buf_t *b = &tcp4_l2_buf[tcp4_l2_buf_used];
uint16_t *check = no_csum ? &(b - 1)->iph.check : NULL;
- len = tcp_l2_buf_fill_headers(c, conn, b, plen, check, seq);
-
iov = tcp4_l2_iov + tcp4_l2_buf_used++;
- iov->iov_len = len + sizeof(b->vnet_len);
+ iov->iov_len = tcp_l2_buf_fill_headers(c, conn, b, plen,
+ check, seq);
if (tcp4_l2_buf_used > ARRAY_SIZE(tcp4_l2_buf) - 1)
tcp_l2_data_buf_flush(c);
} else if (CONN_V6(conn)) {
struct tcp6_l2_buf_t *b = &tcp6_l2_buf[tcp6_l2_buf_used];
- len = tcp_l2_buf_fill_headers(c, conn, b, plen, NULL, seq);
-
iov = tcp6_l2_iov + tcp6_l2_buf_used++;
- iov->iov_len = len + sizeof(b->vnet_len);
+ iov->iov_len = tcp_l2_buf_fill_headers(c, conn, b, plen,
+ NULL, seq);
if (tcp6_l2_buf_used > ARRAY_SIZE(tcp6_l2_buf) - 1)
tcp_l2_data_buf_flush(c);
}
--
@@ -1447,7 +1447,7 @@ void tcp_defer_handler(struct ctx *c)
* @check: Checksum, if already known
* @seq: Sequence number for this segment
*
- * Return: 802.3 length, host order
+ * Return: frame length including L2 headers, host order
*/
static size_t tcp_l2_buf_fill_headers(const struct ctx *c,
const struct tcp_tap_conn *conn,
@@ -1455,7 +1455,7 @@ static size_t tcp_l2_buf_fill_headers(const struct ctx *c,
const uint16_t *check, uint32_t seq)
{
const struct in_addr *a4 = inany_v4(&conn->addr);
- size_t ip_len, eth_len;
+ size_t ip_len, tlen;
#define SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq) \
do { \
@@ -1489,9 +1489,10 @@ do { \
tcp_update_check_tcp4(b);
- eth_len = ip_len + sizeof(struct ethhdr);
+ tlen = ip_len + sizeof(struct ethhdr);
if (c->mode == MODE_PASST)
- b->vnet_len = htonl(eth_len);
+ b->vnet_len = htonl(tlen);
+ tlen += sizeof(b->vnet_len);
} else {
struct tcp6_l2_buf_t *b = (struct tcp6_l2_buf_t *)p;
@@ -1514,14 +1515,14 @@ do { \
b->ip6h.flow_lbl[1] = (conn->sock >> 8) & 0xff;
b->ip6h.flow_lbl[2] = (conn->sock >> 0) & 0xff;
- eth_len = ip_len + sizeof(struct ethhdr);
+ tlen = ip_len + sizeof(struct ethhdr);
if (c->mode == MODE_PASST)
- b->vnet_len = htonl(eth_len);
+ b->vnet_len = htonl(tlen);
+ tlen += sizeof(b->vnet_len);
}
-
#undef SET_TCP_HEADER_COMMON_V4_V6
- return eth_len;
+ return tlen;
}
/**
@@ -1627,8 +1628,8 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
struct tcp6_l2_flags_buf_t *b6 = NULL;
struct tcp_info tinfo = { 0 };
socklen_t sl = sizeof(tinfo);
- size_t optlen = 0, eth_len;
int s = conn->sock;
+ size_t optlen = 0;
struct iovec *iov;
struct tcphdr *th;
char *data;
@@ -1717,9 +1718,8 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
th->syn = !!(flags & SYN);
th->fin = !!(flags & FIN);
- eth_len = tcp_l2_buf_fill_headers(c, conn, p, optlen,
- NULL, conn->seq_to_tap);
- iov->iov_len = eth_len + sizeof(uint32_t);
+ iov->iov_len = tcp_l2_buf_fill_headers(c, conn, p, optlen,
+ NULL, conn->seq_to_tap);
if (th->ack)
conn_flag(c, conn, ~ACK_TO_TAP_DUE);
@@ -2079,25 +2079,22 @@ static void tcp_data_to_tap(struct ctx *c, struct tcp_tap_conn *conn,
ssize_t plen, int no_csum, uint32_t seq)
{
struct iovec *iov;
- size_t len;
if (CONN_V4(conn)) {
struct tcp4_l2_buf_t *b = &tcp4_l2_buf[tcp4_l2_buf_used];
uint16_t *check = no_csum ? &(b - 1)->iph.check : NULL;
- len = tcp_l2_buf_fill_headers(c, conn, b, plen, check, seq);
-
iov = tcp4_l2_iov + tcp4_l2_buf_used++;
- iov->iov_len = len + sizeof(b->vnet_len);
+ iov->iov_len = tcp_l2_buf_fill_headers(c, conn, b, plen,
+ check, seq);
if (tcp4_l2_buf_used > ARRAY_SIZE(tcp4_l2_buf) - 1)
tcp_l2_data_buf_flush(c);
} else if (CONN_V6(conn)) {
struct tcp6_l2_buf_t *b = &tcp6_l2_buf[tcp6_l2_buf_used];
- len = tcp_l2_buf_fill_headers(c, conn, b, plen, NULL, seq);
-
iov = tcp6_l2_iov + tcp6_l2_buf_used++;
- iov->iov_len = len + sizeof(b->vnet_len);
+ iov->iov_len = tcp_l2_buf_fill_headers(c, conn, b, plen,
+ NULL, seq);
if (tcp6_l2_buf_used > ARRAY_SIZE(tcp6_l2_buf) - 1)
tcp_l2_data_buf_flush(c);
}
--
2.39.0
next prev parent reply other threads:[~2023-01-06 0:43 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-06 0:43 [PATCH v3 00/18] RFC: Unify and simplify tap send path David Gibson
2023-01-06 0:43 ` [PATCH v3 01/18] pcap: Introduce pcap_frame() helper David Gibson
2023-01-06 0:43 ` [PATCH v3 02/18] pcap: Replace pcapm() with pcap_multiple() David Gibson
2023-01-06 0:43 ` [PATCH v3 03/18] tcp: Combine two parts of passt tap send path together David Gibson
2023-01-06 0:43 ` [PATCH v3 04/18] tcp: Don't compute total bytes in a message until we need it David Gibson
2023-01-06 0:43 ` [PATCH v3 05/18] tcp: Improve interface to tcp_l2_buf_flush() David Gibson
2023-01-06 0:43 ` [PATCH v3 06/18] tcp: Combine two parts of pasta tap send path together David Gibson
2023-02-13 1:13 ` Stefano Brivio
2023-01-06 0:43 ` [PATCH v3 07/18] tap, tcp: Move tap send path to tap.c David Gibson
2023-01-06 0:43 ` [PATCH v3 08/18] util: Introduce hton*_constant() in place of #ifdefs David Gibson
2023-01-06 0:43 ` [PATCH v3 09/18] tcp, udp: Use named field initializers in iov_init functions David Gibson
2023-01-06 0:43 ` [PATCH v3 10/18] util: Parameterize ethernet header initializer macro David Gibson
2023-01-06 0:43 ` [PATCH v3 11/18] tcp: Remove redundant and incorrect initialization from *_iov_init() David Gibson
2023-01-06 0:43 ` David Gibson [this message]
2023-01-06 0:43 ` [PATCH v3 13/18] tap: Add "tap headers" abstraction David Gibson
2023-01-06 0:43 ` [PATCH v3 14/18] tcp: Use abstracted tap header David Gibson
2023-01-06 0:43 ` [PATCH v3 15/18] tap: Use different io vector bases depending on tap type David Gibson
2023-01-06 0:43 ` [PATCH v3 16/18] udp: Use abstracted tap header David Gibson
2023-01-06 0:43 ` [PATCH v3 17/18] tap: Improve handling of partial frame sends David Gibson
2023-01-06 0:43 ` [PATCH v3 18/18] udp: Use tap_send_frames() David Gibson
2023-01-24 21:20 ` [PATCH v3 00/18] RFC: Unify and simplify tap send path Stefano Brivio
2023-01-25 3:13 ` David Gibson
2023-01-25 23:21 ` Stefano Brivio
2023-02-13 1:14 ` Stefano Brivio
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