libgtp: Allow each PDP context to specify if it transmits G-PDU sequence numbers
GTP sequence numbers on GTP-U are optional for G-PDU type messages (i.e.
user-ip messages). Let's allow the user to specify this behavior by
a new pdu_t.tx_gpdu_seq flag. The flag is enabled by default to stay
compatible with the prior behaviour.
Related: OS#2519
Change-Id: Icf22a2ddd5c4a968ef5bda7c202b921d93fb49e6
diff --git a/gtp/gtp.c b/gtp/gtp.c
index ebbad91..fee49b5 100644
--- a/gtp/gtp.c
+++ b/gtp/gtp.c
@@ -3186,20 +3186,30 @@
get_default_gtp(0, GTP_GPDU, &packet);
packet.gtp0.h.length = hton16(len);
- packet.gtp0.h.seq = hton16(pdp->gtpsntx++);
+ if (pdp->tx_gpdu_seq)
+ packet.gtp0.h.seq = hton16(pdp->gtpsntx++);
+ else
+ packet.gtp0.h.seq = 0;
packet.gtp0.h.flow = hton16(pdp->flru);
packet.gtp0.h.tid = htobe64(pdp_gettid(pdp->imsi, pdp->nsapi));
} else if (pdp->version == 1) {
- iov[0].iov_len = GTP1_HEADER_SIZE_LONG;
addr.sin_port = htons(GTP1U_PORT);
fd = gsn->fd1u;
get_default_gtp(1, GTP_GPDU, &packet);
- packet.gtp1l.h.length = hton16(len - GTP1_HEADER_SIZE_SHORT +
- GTP1_HEADER_SIZE_LONG);
- packet.gtp1l.h.seq = hton16(pdp->gtpsntx++);
- packet.gtp1l.h.tei = hton32(pdp->teid_gn);
+ if (pdp->tx_gpdu_seq) {
+ packet.gtp1l.h.seq = hton16(pdp->gtpsntx++);
+ packet.gtp1l.h.length = hton16(len - GTP1_HEADER_SIZE_SHORT +
+ GTP1_HEADER_SIZE_LONG);
+ packet.gtp1l.h.tei = hton32(pdp->teid_gn);
+ iov[0].iov_len = GTP1_HEADER_SIZE_LONG;
+ } else {
+ packet.gtp1s.h.flags &= ~GTP1HDR_F_SEQ;
+ packet.gtp1s.h.length = hton16(len);
+ packet.gtp1s.h.tei = hton32(pdp->teid_gn);
+ iov[0].iov_len = GTP1_HEADER_SIZE_SHORT;
+ }
} else {
LOGP(DLGTP, LOGL_ERROR, "Unknown version: %d\n", pdp->version);
return EOF;