<p>pespin has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/c/osmo-ggsn/+/23860">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">gtp: Rework parsing logic of UpdatePdpCtxResponse<br><br>The previous order of parsing lead to non-optimal information gathering<br>when pushing events to upper layers.<br><br>This patch rearranges parsing of packet data to always gather as much<br>info as possible for the benefit of the upper layer. This way it can<br>gather information such as the cause, which is important in the case of<br>"Non-existent", since user should then drop the context.<br><br>First we want to parse the recovery state, but delay cb to upper layers<br>until we tried to gather the pdp ctx (meaning all except that pdp ctx<br>should be freed).<br>Second, we want to parse the cause, in order to know if there's an<br>associated pdp ctx we can gather from TEID.<br>Third, once we know if we should expect a meaningul TEID, parse it.<br><br>Related: SYS#5435<br>Change-Id: Idd10b494e8fbac8703c49ecd8f9bbe4246e51c57<br>---<br>M gtp/gtp.c<br>1 file changed, 30 insertions(+), 19 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/osmo-ggsn refs/changes/60/23860/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/gtp/gtp.c b/gtp/gtp.c</span><br><span>index 701aa36..1995d10 100644</span><br><span>--- a/gtp/gtp.c</span><br><span>+++ b/gtp/gtp.c</span><br><span>@@ -2324,26 +2324,20 @@</span><br><span> static int gtp_update_pdp_conf(struct gsn_t *gsn, uint8_t version,</span><br><span> struct sockaddr_in *peer, void *pack, unsigned len)</span><br><span> {</span><br><span style="color: hsl(0, 100%, 40%);">- struct pdp_t *pdp;</span><br><span style="color: hsl(120, 100%, 40%);">+ struct pdp_t *pdp = NULL;</span><br><span> union gtpie_member *ie[GTPIE_SIZE];</span><br><span style="color: hsl(0, 100%, 40%);">- uint8_t cause, recovery;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t cause = EOF;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t recovery;</span><br><span style="color: hsl(120, 100%, 40%);">+ int rc = 0;</span><br><span> void *cbp = NULL;</span><br><span> uint8_t type = 0;</span><br><span style="color: hsl(120, 100%, 40%);">+ bool trigger_recovery = false;</span><br><span> int hlen = get_hlen(pack);</span><br><span> </span><br><span> /* Remove packet from queue */</span><br><span> if (gtp_conf(gsn, 0, peer, pack, len, &type, &cbp))</span><br><span> return EOF;</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- /* Find the context in question */</span><br><span style="color: hsl(0, 100%, 40%);">- if (gtp_pdp_getgtp1(gsn, &pdp, get_tei(pack))) {</span><br><span style="color: hsl(0, 100%, 40%);">- gsn->err_unknownpdp++;</span><br><span style="color: hsl(0, 100%, 40%);">- GTP_LOGPKG(LOGL_ERROR, peer, pack, len,</span><br><span style="color: hsl(0, 100%, 40%);">- "Unknown PDP context: %u\n", get_tei(pack));</span><br><span style="color: hsl(0, 100%, 40%);">- pdp = NULL;</span><br><span style="color: hsl(0, 100%, 40%);">- goto err_out;</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span> /* Decode information elements */</span><br><span> if (gtpie_decaps(ie, version, pack + hlen, len - hlen)) {</span><br><span> gsn->invalid++;</span><br><span>@@ -2352,19 +2346,34 @@</span><br><span> goto err_out;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* Extract recovery (optional) */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!gtpie_gettv1(ie, GTPIE_RECOVERY, 0, &recovery))</span><br><span style="color: hsl(120, 100%, 40%);">+ trigger_recovery = true;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /* Extract cause value (mandatory) */</span><br><span> if (gtpie_gettv1(ie, GTPIE_CAUSE, 0, &cause)) {</span><br><span> goto err_missing;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- /* Extract recovery (optional) */</span><br><span style="color: hsl(0, 100%, 40%);">- if (!gtpie_gettv1(ie, GTPIE_RECOVERY, 0, &recovery)) {</span><br><span style="color: hsl(0, 100%, 40%);">- emit_cb_recovery(gsn, peer, pdp, recovery);</span><br><span style="color: hsl(120, 100%, 40%);">+ /* 3GPP TS 29.060 sec 8.2: "Receiving node shall send back to the source</span><br><span style="color: hsl(120, 100%, 40%);">+ * of the message, a response with the appropriate cause value (either</span><br><span style="color: hsl(120, 100%, 40%);">+ * "Non-existent" or "Context not found"). The Tunnel Endpoint</span><br><span style="color: hsl(120, 100%, 40%);">+ * Identifier used in the response message shall be set to all zeroes."</span><br><span style="color: hsl(120, 100%, 40%);">+ * Hence, TEID=0 in this scenario, it makes no sense to infer PDP ctx</span><br><span style="color: hsl(120, 100%, 40%);">+ * from it. User is responsible to infer it from cbp */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (cause != GTPCAUSE_NON_EXIST || cause != GTPCAUSE_CONTEXT_NOT_FOUND) {</span><br><span style="color: hsl(120, 100%, 40%);">+ /* Find the context in question */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (gtp_pdp_getgtp1(gsn, &pdp, get_tei(pack))) {</span><br><span style="color: hsl(120, 100%, 40%);">+ gsn->err_unknownpdp++;</span><br><span style="color: hsl(120, 100%, 40%);">+ GTP_LOGPKG(LOGL_ERROR, peer, pack, len,</span><br><span style="color: hsl(120, 100%, 40%);">+ "Unknown PDP context: %u\n", get_tei(pack));</span><br><span style="color: hsl(120, 100%, 40%);">+ goto err_out;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span> }</span><br><span> </span><br><span> /* Check all conditional information elements */</span><br><span> /* TODO: This does not handle GGSN-initiated update responses */</span><br><span style="color: hsl(0, 100%, 40%);">- if (GTPCAUSE_ACC_REQ == cause) {</span><br><span style="color: hsl(120, 100%, 40%);">+ if (cause == GTPCAUSE_ACC_REQ) {</span><br><span> if (version == 0) {</span><br><span> if (gtpie_gettv0(ie, GTPIE_QOS_PROFILE0, 0,</span><br><span> &pdp->qos_neg0,</span><br><span>@@ -2416,18 +2425,20 @@</span><br><span> }</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+generic_ret:</span><br><span style="color: hsl(120, 100%, 40%);">+ if (trigger_recovery)</span><br><span style="color: hsl(120, 100%, 40%);">+ emit_cb_recovery(gsn, peer, pdp, recovery);</span><br><span> if (gsn->cb_conf)</span><br><span> gsn->cb_conf(type, cause, pdp, cbp);</span><br><span style="color: hsl(0, 100%, 40%);">- return 0; /* Succes */</span><br><span style="color: hsl(120, 100%, 40%);">+ return rc; /* Succes */</span><br><span> </span><br><span> err_missing:</span><br><span> gsn->missing++;</span><br><span> GTP_LOGPKG(LOGL_ERROR, peer, pack, len,</span><br><span> "Missing information field\n");</span><br><span> err_out:</span><br><span style="color: hsl(0, 100%, 40%);">- if (gsn->cb_conf)</span><br><span style="color: hsl(0, 100%, 40%);">- gsn->cb_conf(type, EOF, pdp, cbp);</span><br><span style="color: hsl(0, 100%, 40%);">- return EOF;</span><br><span style="color: hsl(120, 100%, 40%);">+ rc = EOF;</span><br><span style="color: hsl(120, 100%, 40%);">+ goto generic_ret;</span><br><span> }</span><br><span> </span><br><span> /* API: Deprecated. Send Delete PDP Context Request And free pdp ctx. */</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-ggsn/+/23860">change 23860</a>. To unsubscribe, or for help writing mail filters, visit <a href="https://gerrit.osmocom.org/settings">settings</a>.</p><div itemscope itemtype="http://schema.org/EmailMessage"><div itemscope itemprop="action" itemtype="http://schema.org/ViewAction"><link itemprop="url" href="https://gerrit.osmocom.org/c/osmo-ggsn/+/23860"/><meta itemprop="name" content="View Change"/></div></div>
<div style="display:none"> Gerrit-Project: osmo-ggsn </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: Idd10b494e8fbac8703c49ecd8f9bbe4246e51c57 </div>
<div style="display:none"> Gerrit-Change-Number: 23860 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: pespin <pespin@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>