- if (flow->nw_proto == IP_TYPE_TCP
- || flow->nw_proto == IP_TYPE_UDP) {
- const struct udp_header *th;
- th = packet->l4 = buffer_at(&b, ip_len, sizeof *th);
- if (th) {
- flow->tp_src = th->udp_src;
- flow->tp_dst = th->udp_dst;
- } else {
- /* Avoid tricking other code into thinking that this
- * packet has an L4 header. */
- flow->nw_proto = 0;
+ packet->l4 = b.data;
+ if (!IP_IS_FRAGMENT(nh->ip_frag_off)) {
+ if (flow->nw_proto == IP_TYPE_TCP) {
+ const struct tcp_header *tcp = pull_tcp(&b);
+ if (tcp) {
+ flow->tp_src = tcp->tcp_src;
+ flow->tp_dst = tcp->tcp_dst;
+ packet->l7 = b.data;
+ } else {
+ /* Avoid tricking other code into thinking that
+ * this packet has an L4 header. */
+ flow->nw_proto = 0;
+ }
+ } else if (flow->nw_proto == IP_TYPE_UDP) {
+ const struct udp_header *udp = pull_udp(&b);
+ if (udp) {
+ flow->tp_src = udp->udp_src;
+ flow->tp_dst = udp->udp_dst;
+ packet->l7 = b.data;
+ } else {
+ /* Avoid tricking other code into thinking that
+ * this packet has an L4 header. */
+ flow->nw_proto = 0;
+ }
+ } else if (flow->nw_proto == IP_TYPE_ICMP) {
+ const struct icmp_header *icmp = pull_icmp(&b);
+ if (icmp) {
+ flow->icmp_type = htons(icmp->icmp_type);
+ flow->icmp_code = htons(icmp->icmp_code);
+ packet->l7 = b.data;
+ } else {
+ /* Avoid tricking other code into thinking that
+ * this packet has an L4 header. */
+ flow->nw_proto = 0;
+ }