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-rw-r--r--trafgen_l4.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/trafgen_l4.c b/trafgen_l4.c
index ee8deb4..b3b0775 100644
--- a/trafgen_l4.c
+++ b/trafgen_l4.c
@@ -118,13 +118,20 @@ static void tcp_header_init(struct proto_hdr *hdr)
proto_field_set_default_be16(hdr, TCP_DOFF, 5);
}
-static void tcp_packet_finish(struct proto_hdr *hdr)
+static void tcp_field_changed(struct proto_field *field)
+{
+ field->hdr->is_csum_valid = false;
+}
+
+static void tcp_csum_update(struct proto_hdr *hdr)
{
struct proto_hdr *lower = proto_lower_header(hdr);
struct packet *pkt = current_packet();
uint16_t total_len;
uint16_t csum;
+ if (hdr->is_csum_valid)
+ return;
if (proto_field_is_set(hdr, TCP_CSUM))
return;
@@ -133,6 +140,8 @@ static void tcp_packet_finish(struct proto_hdr *hdr)
total_len = pkt->len - hdr->pkt_offset;
+ proto_field_set_default_be16(hdr, TCP_CSUM, 0);
+
switch (lower->ops->id) {
case PROTO_IP4:
csum = p4_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr),
@@ -147,14 +156,17 @@ static void tcp_packet_finish(struct proto_hdr *hdr)
break;
}
- proto_field_set_be16(hdr, TCP_CSUM, bswap_16(csum));
+ proto_field_set_default_be16(hdr, TCP_CSUM, bswap_16(csum));
+ hdr->is_csum_valid = true;
}
static const struct proto_ops tcp_proto_ops = {
.id = PROTO_TCP,
.layer = PROTO_L4,
.header_init = tcp_header_init,
- .packet_finish = tcp_packet_finish,
+ .packet_update = tcp_csum_update,
+ .packet_finish = tcp_csum_update,
+ .field_changed = tcp_field_changed,
};
static struct proto_field icmpv4_fields[] = {