diff options
Diffstat (limited to 'channels/chan_sip.c')
| -rw-r--r-- | channels/chan_sip.c | 122 |
1 files changed, 105 insertions, 17 deletions
diff --git a/channels/chan_sip.c b/channels/chan_sip.c index c2afeb5ad..a3d1ef61f 100644 --- a/channels/chan_sip.c +++ b/channels/chan_sip.c @@ -7134,8 +7134,8 @@ struct sip_pvt *sip_alloc(ast_string_field callid, struct ast_sockaddr *addr, return NULL; } - /* If this dialog is created as the result of an incoming Request. Lets store - * some information about that request */ + /* If this dialog is created as a result of a request or response, lets store + * some information about it in the dialog. */ if (req) { char *sent_by, *branch; const char *cseq = get_header(req, "Cseq"); @@ -7267,6 +7267,9 @@ struct match_req_args { const char *fromtag; unsigned int seqno; + /* Set if this method is a Response */ + int respid; + /* Set if the method is a Request */ const char *ruri; const char *viabranch; @@ -7279,7 +7282,8 @@ struct match_req_args { enum match_req_res { SIP_REQ_MATCH, SIP_REQ_NOT_MATCH, - SIP_REQ_LOOP_DETECTED, + SIP_REQ_LOOP_DETECTED, /* multiple incoming requests with same call-id but different branch parameters have been detected */ + SIP_REQ_FORKED, /* An outgoing request has been forked as result of receiving two differing 200ok responses. */ }; /* @@ -7302,6 +7306,12 @@ static enum match_req_res match_req_to_dialog(struct sip_pvt *sip_pvt_ptr, struc return SIP_REQ_NOT_MATCH; } if (arg->method == SIP_RESPONSE) { + /* Verify fromtag of response matches the tag we gave them. */ + if (strcmp(arg->fromtag, sip_pvt_ptr->tag)) { + /* fromtag from response does not match our tag */ + return SIP_REQ_NOT_MATCH; + } + /* Verify totag if we have one stored for this dialog, but never be strict about this for * a response until the dialog is established */ if (!ast_strlen_zero(sip_pvt_ptr->theirtag) && ast_test_flag(&sip_pvt_ptr->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED)) { @@ -7309,16 +7319,36 @@ static enum match_req_res match_req_to_dialog(struct sip_pvt *sip_pvt_ptr, struc /* missing totag when they already gave us one earlier */ return SIP_REQ_NOT_MATCH; } + /* compare the totag of response with the tag we have stored for them */ if (strcmp(arg->totag, sip_pvt_ptr->theirtag)) { - /* The totag of the response does not match the one we have stored */ + /* totag did not match what we had stored for them. */ + char invite_branch[32] = { 0, }; + if (sip_pvt_ptr->invite_branch) { + snprintf(invite_branch, sizeof(invite_branch), "z9hG4bK%08x", (int) sip_pvt_ptr->invite_branch); + } + /* Forked Request Detection + * + * If this is a 200ok response and the totags do not match, this + * might be a forked response to an outgoing Request. Detection of + * a forked response must meet the criteria below. + * + * 1. must be a 2xx Response + * 2. call-d equal to call-id of Request. this is done earlier + * 3. from-tag equal to from-tag of Request. this is done earlier + * 4. branch parameter equal to branch of inital Request + * 5. to-tag _NOT_ equal to previous 2xx response that already established the dialog. + */ + if ((arg->respid == 200) && + !ast_strlen_zero(invite_branch) && + !ast_strlen_zero(arg->viabranch) && + !strcmp(invite_branch, arg->viabranch)) { + return SIP_REQ_FORKED; + } + + /* The totag did not match the one we had stored, and this is not a Forked Request. */ return SIP_REQ_NOT_MATCH; } } - /* Verify fromtag of response matches the tag we gave them. */ - if (strcmp(arg->fromtag, sip_pvt_ptr->tag)) { - /* fromtag from response does not match our tag */ - return SIP_REQ_NOT_MATCH; - } } else { /* Verify the fromtag of Request matches the tag they provided earlier. * If this is a Request with authentication credentials, forget their old @@ -7414,6 +7444,37 @@ static enum match_req_res match_req_to_dialog(struct sip_pvt *sip_pvt_ptr, struc return SIP_REQ_MATCH; } +/*! \brief This function creates a dialog to handle a forked request. This dialog + * exists only to properly terminiate the the forked request immediately. + */ +static void forked_invite_init(struct sip_request *req, const char *new_theirtag, struct sip_pvt *original, struct ast_sockaddr *addr) +{ + struct sip_pvt *p; + + if (!(p = sip_alloc(original->callid, addr, 1, SIP_INVITE, req))) { + return; /* alloc error */ + } + p->invitestate = INV_TERMINATED; + p->ocseq = original->ocseq; + p->branch = original->branch; + + memcpy(&p->flags, &original->flags, sizeof(p->flags)); + copy_request(&p->initreq, &original->initreq); + ast_string_field_set(p, theirtag, new_theirtag); + ast_copy_string(p->tag, original->tag, sizeof(p->tag)); + ast_string_field_set(p, uri, original->uri); + ast_string_field_set(p, our_contact, original->our_contact); + ast_string_field_set(p, fullcontact, original->fullcontact); + parse_ok_contact(p, req); + build_route(p, req, 1); + + transmit_request(p, SIP_ACK, p->ocseq, XMIT_UNRELIABLE, TRUE); + transmit_request(p, SIP_BYE, 0, XMIT_RELIABLE, TRUE); + + pvt_set_needdestroy(p, "forked request"); /* this dialog will terminate once the BYE is responed to or times out. */ + dialog_unref(p, "setup forked invite termination"); +} + /*! \brief find or create a dialog structure for an incoming SIP message. * Connect incoming SIP message to current dialog or create new dialog structure * Returns a reference to the sip_pvt object, remember to give it back once done. @@ -7485,6 +7546,9 @@ static struct sip_pvt *find_call(struct sip_request *req, struct ast_sockaddr *a struct sip_pvt tmp_dialog = { .callid = callid, }; + /* if a Outbound forked Request is detected, this pvt will point + * to the dialog the Request is forking off of. */ + struct sip_pvt *fork_pvt = NULL; struct match_req_args args = { 0, }; int found; struct ao2_iterator *iterator = ao2_t_callback(dialogs, @@ -7498,14 +7562,20 @@ static struct sip_pvt *find_call(struct sip_request *req, struct ast_sockaddr *a args.totag = totag; args.fromtag = fromtag; args.seqno = seqno; - - /* If this is a Request, set the Via and Authorization header arguments */ - if (req->method != SIP_RESPONSE) { - args.ruri = REQ_OFFSET_TO_STR(req, rlPart2); - get_viabranch(ast_strdupa(get_header(req, "Via")), (char **) &args.viasentby, (char **) &args.viabranch); - if (!ast_strlen_zero(get_header(req, "Authorization")) || - !ast_strlen_zero(get_header(req, "Proxy-Authorization"))) { - args.authentication_present = 1; + /* get via header information. */ + args.ruri = REQ_OFFSET_TO_STR(req, rlPart2); + get_viabranch(ast_strdupa(get_header(req, "Via")), (char **) &args.viasentby, (char **) &args.viabranch); + /* determine if this is a Request with authentication credentials. */ + if (!ast_strlen_zero(get_header(req, "Authorization")) || + !ast_strlen_zero(get_header(req, "Proxy-Authorization"))) { + args.authentication_present = 1; + } + /* if it is a response, get the response code */ + if (req->method == SIP_RESPONSE) { + const char* e = ast_skip_blanks(REQ_OFFSET_TO_STR(req, rlPart2)); + int respid; + if (!ast_strlen_zero(e) && (sscanf(e, "%30d", &respid) == 1)) { + args.respid = respid; } } @@ -7517,6 +7587,7 @@ static struct sip_pvt *find_call(struct sip_request *req, struct ast_sockaddr *a case SIP_REQ_MATCH: sip_pvt_lock(sip_pvt_ptr); ao2_iterator_destroy(iterator); + dialog_unref(fork_pvt, "unref fork_pvt"); return sip_pvt_ptr; /* return pvt with ref */ case SIP_REQ_LOOP_DETECTED: /* This is likely a forked Request that somehow resulted in us receiving multiple parts of the fork. @@ -7524,7 +7595,12 @@ static struct sip_pvt *find_call(struct sip_request *req, struct ast_sockaddr *a transmit_response_using_temp(callid, addr, 1, intended_method, req, "482 (Loop Detected)"); dialog_unref(sip_pvt_ptr, "pvt did not match incoming SIP msg, unref from search."); ao2_iterator_destroy(iterator); + dialog_unref(fork_pvt, "unref fork_pvt"); return NULL; + case SIP_REQ_FORKED: + dialog_unref(fork_pvt, "throwing way pvt to fork off of."); + fork_pvt = dialog_ref(sip_pvt_ptr, "this pvt has a forked request, save this off to copy information into new dialog\n"); + /* fall through */ case SIP_REQ_NOT_MATCH: default: dialog_unref(sip_pvt_ptr, "pvt did not match incoming SIP msg, unref from search"); @@ -7533,6 +7609,18 @@ static struct sip_pvt *find_call(struct sip_request *req, struct ast_sockaddr *a if (iterator) { ao2_iterator_destroy(iterator); } + + /* Handle any possible forked requests. This must be done only after transaction matching is complete. */ + if (fork_pvt) { + /* XXX right now we only support handling forked INVITE Requests. Any other + * forked request type must be added here. */ + if (fork_pvt->method == SIP_INVITE) { + forked_invite_init(req, args.totag, fork_pvt, addr); + dialog_unref(fork_pvt, "throwing way old forked pvt"); + return NULL; + } + fork_pvt = dialog_unref(fork_pvt, "throwing way pvt to fork off of"); + } } /* end of pedantic mode Request/Reponse to Dialog matching */ /* See if the method is capable of creating a dialog */ |