Both tcp_data_from_tap() and tcp_tap_handler() call packet_get() to get
the entire L4 packet length, then immediately call it again to check that
the packet is long enough to include a TCP header. The features of
packet_get() let us easily combine these together, we just need to adjust
the length slightly, because we want the value to include the TCP header
length.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
tcp.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)
diff --git a/tcp.c b/tcp.c
index d8c2327..6a34f82 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2320,16 +2320,12 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn
*conn,
char *data;
size_t off;
- if (!packet_get(p, i, 0, 0, &len)) {
- tcp_rst(c, conn);
- return;
- }
-
- th = packet_get(p, i, 0, sizeof(*th), NULL);
+ th = packet_get(p, i, 0, sizeof(*th), &len);
if (!th) {
tcp_rst(c, conn);
return;
}
+ len += sizeof(*th);
off = th->doff * 4UL;
if (off < sizeof(*th) || off > len) {
@@ -2545,12 +2541,10 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr,
const void *daddr,
int ack_due = 0;
char *opts;
- if (!packet_get(p, idx, 0, 0, &len))
- return 1;
-
- th = packet_get(p, idx, 0, sizeof(*th), NULL);
+ th = packet_get(p, idx, 0, sizeof(*th), &len);
if (!th)
return 1;
+ len += sizeof(*th);
optlen = th->doff * 4UL - sizeof(*th);
/* Static checkers might fail to see this: */
--
2.41.0