tap, tcp: Fix two comparisons with different signedness reported by gcc 7

For some reason, those are not reported by recent versions of gcc.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/tcp.c b/tcp.c
index b0d5f40..2a842bd 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1034,7 +1034,7 @@ static int tcp_opt_get(struct tcphdr *th, size_t len, uint8_t type_search,
 	uint8_t type, optlen;
 	char *p;
 
-	if (len > th->doff * 4)
+	if (len > (unsigned)th->doff * 4)
 		len = th->doff * 4;
 
 	len -= sizeof(*th);