tcp_update_csum() is now simple enough that it makes sense to just fold it
into tcp_fill_header(), meaning the latter now really does fill all the
header fields.
Signed-off-by: David Gibson
---
tcp.c | 66 ++++++++++++++++++++++++++---------------------------------
1 file changed, 29 insertions(+), 37 deletions(-)
diff --git a/tcp.c b/tcp.c
index e9f62a4..88a285b 100644
--- a/tcp.c
+++ b/tcp.c
@@ -750,23 +750,6 @@ static void tcp_sock_set_bufsize(const struct ctx *c, int s)
trace("TCP: failed to set SO_SNDBUF to %i", v);
}
-/**
- * tcp_update_csum() - Calculate TCP checksum
- * @psum: Unfolded partial checksum of the IPv4 or IPv6 pseudo-header
- * @th: TCP header (updated)
- * @iov: IO vector containing the TCP payload
- * @iov_cnt: Length of @iov
- * @doffset: TCP payload offset in @iov
- */
-static void tcp_update_csum(uint32_t psum, struct tcphdr *th,
- const struct iovec *iov, int iov_cnt,
- size_t doffset)
-{
- th->check = 0;
- psum = csum_unfolded(th, sizeof(*th), psum);
- th->check = csum_iov(iov, iov_cnt, doffset, psum);
-}
-
/**
* tcp_opt_get() - Get option, and value if any, from TCP header
* @opts: Pointer to start of TCP options in header
@@ -860,9 +843,16 @@ void tcp_defer_handler(struct ctx *c)
* @th: Pointer to the TCP header structure
* @conn: Pointer to the TCP connection structure
* @seq: Sequence number
+ * @ppsum: Pointer to pseudo-header checksum, or NULL to omit checksum
+ * @iov: IO vector containing the TCP payload
+ * @iov_cnt: Length of @iov
+ * @doffset: TCP payload offset in @iov
*/
static void tcp_fill_header(struct tcphdr *th,
- const struct tcp_tap_conn *conn, uint32_t seq)
+ const struct tcp_tap_conn *conn, uint32_t seq,
+ const uint32_t *ppsum,
+ const struct iovec *iov, size_t iov_cnt,
+ size_t doffset)
{
const struct flowside *tapside = TAPFLOW(conn);
@@ -877,6 +867,11 @@ static void tcp_fill_header(struct tcphdr *th,
th->window = htons(MIN(wnd, USHRT_MAX));
}
+ th->check = 0;
+ if (ppsum) {
+ uint32_t sum = csum_unfolded(th, sizeof(*th), *ppsum);
+ th->check = csum_iov(iov, iov_cnt, doffset, sum);
+ }
}
/**
@@ -904,6 +899,8 @@ void tcp_fill_headers4(const struct tcp_tap_conn *conn,
size_t dlen = iov_size(iov, iov_cnt) - doffset;
size_t l4len = dlen + sizeof(*th);
size_t l3len = l4len + sizeof(*iph);
+ const uint32_t *ppsum = NULL;
+ uint32_t psum;
ASSERT(src4 && dst4);
@@ -914,17 +911,13 @@ void tcp_fill_headers4(const struct tcp_tap_conn *conn,
iph->check = check ? *check :
csum_ip4_header(l3len, IPPROTO_TCP, *src4, *dst4);
- tcp_fill_header(th, conn, seq);
-
- if (no_tcp_csum) {
- th->check = 0;
- } else {
- uint32_t psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP,
- *src4, *dst4);
-
- tcp_update_csum(psum, th, iov, iov_cnt, doffset);
+ if (!no_tcp_csum) {
+ psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP, *src4, *dst4);
+ ppsum = &psum;
}
+ tcp_fill_header(th, conn, seq, ppsum, iov, iov_cnt, doffset);
+
tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
}
@@ -950,6 +943,8 @@ void tcp_fill_headers6(const struct tcp_tap_conn *conn,
const struct flowside *tapside = TAPFLOW(conn);
size_t dlen = iov_size(iov, iov_cnt) - doffset;
size_t l4len = dlen + sizeof(*th);
+ const uint32_t *ppsum = NULL;
+ uint32_t psum;
ip6h->payload_len = htons(l4len);
ip6h->saddr = tapside->oaddr.a6;
@@ -963,18 +958,15 @@ void tcp_fill_headers6(const struct tcp_tap_conn *conn,
ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
- tcp_fill_header(th, conn, seq);
-
- if (no_tcp_csum) {
- th->check = 0;
- } else {
- uint32_t psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
- &ip6h->saddr,
- &ip6h->daddr);
-
- tcp_update_csum(psum, th, iov, iov_cnt, doffset);
+ if (!no_tcp_csum) {
+ psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
+ &ip6h->saddr,
+ &ip6h->daddr);
+ ppsum = &psum;
}
+ tcp_fill_header(th, conn, seq, ppsum, iov, iov_cnt, doffset);
+
tap_hdr_update(taph, l4len + sizeof(*ip6h) + sizeof(struct ethhdr));
}
--
2.47.0