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authorNeels Hofmeyr <nhofmeyr@sysmocom.de>2015-10-12 14:26:49 +0200
committerNeels Hofmeyr <nhofmeyr@sysmocom.de>2015-10-19 14:08:28 +0200
commit85c25ac91c5fe6e87e1c417ea3543149a92d4145 (patch)
treeefa5d1aca9e7b0bc43acdaa5ab54c741bce7f814
parent9a5cfa49ad1ce6d2cf6e9295a423e880d72dd1b5 (diff)
comments: add/replace.
Sponsored-by: On-Waves ehi
-rw-r--r--gtp/gtp.c35
1 files changed, 26 insertions, 9 deletions
diff --git a/gtp/gtp.c b/gtp/gtp.c
index 4fab3c5..d9f17c1 100644
--- a/gtp/gtp.c
+++ b/gtp/gtp.c
@@ -614,6 +614,15 @@ int gtp_notification(struct gsn_t *gsn, int version,
return 0;
}
+/* Look for a message in the response queue for the given peer and sequence
+ * number seq. If found, (re-)send the response message and return 0. Otherwise
+ * return nonzero. This allows catching duplicate messages.
+ * A response message stays in the response queue until it times out.
+ * So, for any number of identical requests within that timeout period, the
+ * same packet can be resent.
+ * TODO this only checks the peer and sequence number, and does not verify that
+ * the GTP request is identical to the previous one for this peer and sequence
+ * nr: a mere peer or seq glitch can cause leaks of previous responses. */
int gtp_duplicate(struct gsn_t *gsn, int version,
struct sockaddr_in *peer, uint16_t seq)
{
@@ -636,6 +645,8 @@ int gtp_duplicate(struct gsn_t *gsn, int version,
qmsg->fd, (unsigned long)&qmsg->p, qmsg->l,
strerror(errno));
}
+
+ /* TODO: qmsg->retrans++ ? */
return 0;
}
@@ -873,7 +884,7 @@ int gtp_echo_ind(struct gsn_t *gsn, int version, struct sockaddr_in *peer,
int fd, void *pack, unsigned len)
{
- /* Check if it was a duplicate request */
+ /* Repeat previous response in case of duplicate request */
if (!gtp_duplicate(gsn, 0, peer, get_seq(pack)))
return 0;
@@ -1258,6 +1269,7 @@ int gtp_create_pdp_ind(struct gsn_t *gsn, int version,
uint8_t linked_nsapi = 0;
struct pdp_t *linked_pdp = NULL;
+ /* Repeat previous response in case of duplicate request */
if (!gtp_duplicate(gsn, version, peer, seq))
return 0;
@@ -1265,6 +1277,7 @@ int gtp_create_pdp_ind(struct gsn_t *gsn, int version,
memset(pdp, 0, sizeof(struct pdp_t));
if (version == 0) {
+ /* TODO code dup: get_tid() */
uint64_t tid = be64toh(((union gtp_packet *)pack)->gtp0.h.tid);
pdp_set_imsi_nsapi(pdp, tid);
@@ -1953,10 +1966,9 @@ int gtp_update_pdp_ind(struct gsn_t *gsn, int version,
uint64_t imsi;
uint8_t nsapi;
- /* Is this a duplicate ? */
- if (!gtp_duplicate(gsn, version, peer, seq)) {
- return 0; /* We already sent of response once */
- }
+ /* Repeat previous response in case of duplicate request */
+ if (!gtp_duplicate(gsn, version, peer, seq))
+ return 0;
/* Decode information elements */
if (gtpie_decaps(ie, version, pack + hlen, len - hlen)) {
@@ -2179,6 +2191,9 @@ int gtp_update_pdp_conf(struct gsn_t *gsn, int version,
if (gtp_conf(gsn, 0, peer, pack, len, &type, &cbp))
return EOF;
+ /* TODO This function is called from gtp_decaps1c() (for GTP v1) but
+ * uses gtp0.h.flow (GTP v0 data element)
+ */
/* Find the context in question */
if (pdp_getgtp0(&pdp, ntoh16(((union gtp_packet *)pack)->gtp0.h.flow))) {
gsn->err_unknownpdp++;
@@ -2192,6 +2207,9 @@ int gtp_update_pdp_conf(struct gsn_t *gsn, int version,
/* Register that we have received a valid teic from GGSN */
pdp->teic_confirmed = 1;
+ /* TODO This function is called from gtp_decaps1c() (for GTP v1) but
+ * explicitly passes version 0 and GTP0_HEADER_SIZE to gtpie_decaps()
+ */
/* Decode information elements */
if (gtpie_decaps
(ie, 0, pack + GTP0_HEADER_SIZE, len - GTP0_HEADER_SIZE)) {
@@ -2424,10 +2442,9 @@ int gtp_delete_pdp_ind(struct gsn_t *gsn, int version,
int n;
int count = 0;
- /* Is this a duplicate ? */
- if (!gtp_duplicate(gsn, version, peer, seq)) {
- return 0; /* We already sent off response once */
- }
+ /* Repeat previous response in case of duplicate request */
+ if (!gtp_duplicate(gsn, version, peer, seq))
+ return 0;
/* Find the linked context in question */
if (pdp_getgtp1(&linked_pdp, get_tei(pack))) {