[PATCH] gtp_duplicate(): comment, add todo.

--- gtp/gtp.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/gtp/gtp.c b/gtp/gtp.c index e6a610d..de6a7b4 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) { @@ -873,7 +882,7 @@ 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; @@ -1258,7 +1267,7 @@ int gtp_create_pdp_ind(struct gsn_t *gsn, int version, uint8_t linked_nsapi = 0; struct pdp_t *linked_pdp = NULL; - /* TODO describe what this is all about: */ + /* Repeat previous response in case of duplicate request */ if (!gtp_duplicate(gsn, version, peer, seq)) return 0; @@ -1955,10 +1964,9 @@ 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)) { @@ -2432,10 +2440,9 @@ 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))) { -- 2.1.4