/* returns the pointer to the first VIA header */
char *lw_find_via(char *buf, char *buf_end)
{
char *p;
unsigned int val;
/* skip the first line */
p = eat_line(buf, buf_end - buf);
while (buf_end - p > 4) {
val = LOWER_DWORD(READ(p));
if ((val == _via1_) || (val == _via2_)
|| ((LOWER_BYTE(*p) == 'v') /* compact header */
&& ((*(p+1) == ' ') || (*(p+1) == ':')) )
) return p;
p = lw_next_line(p, buf_end);
}
/* not found */
return 0;
}
/* Re-parsing version of build_local() function:
* it builds a local CANCEL or ACK (for non-200 response) request based on
* the previous INVITE which was sent out.
*
* Can not be used to build other type of requests!
*/
char *build_local_reparse(struct cell *Trans,unsigned int branch,
unsigned int *len, char *method, int method_len, str *to
#ifdef CANCEL_REASON_SUPPORT
, struct cancel_reason *reason
#endif /* CANCEL_REASON_SUPPORT */
)
{
char *invite_buf, *invite_buf_end;
char *cancel_buf;
char *s, *s1, *d; /* source and destination buffers */
short invite_len;
enum _hdr_types_t hf_type;
int first_via, to_len;
int cancel_buf_len;
#ifdef CANCEL_REASON_SUPPORT
int reason_len, code_len;
struct hdr_field *reas1, *reas_last, *hdr;
#endif /* CANCEL_REASON_SUPPORT */
int hadded = 0;
sr_cfgenv_t *cenv = NULL;
invite_buf = Trans->uac[branch].request.buffer;
invite_len = Trans->uac[branch].request.buffer_len;
if (!invite_buf || !invite_len) {
LM_ERR("INVITE is missing\n");
goto error;
}
if ((*invite_buf != 'I') && (*invite_buf != 'i')) {
LM_ERR("trying to build with local reparse"
" for a non-INVITE request?\n");
goto error;
}
#ifdef CANCEL_REASON_SUPPORT
reason_len = 0;
reas1 = 0;
reas_last = 0;
/* compute reason size (if no reason or disabled => reason_len == 0)*/
if (reason && reason->cause != CANCEL_REAS_UNKNOWN){
if (likely(reason->cause > 0 &&
cfg_get(tm, tm_cfg, local_cancel_reason))){
/* Reason: SIP;cause=<reason->cause>[;text=<reason->u.text.s>] */
reason_len = REASON_PREFIX_LEN + USHORT2SBUF_MAX_LEN +
(reason->u.text.s?
REASON_TEXT_LEN + 1 + reason->u.text.len + 1 : 0) +
CRLF_LEN;
} else if (likely(reason->cause == CANCEL_REAS_PACKED_HDRS &&
!(Trans->flags & T_NO_E2E_CANCEL_REASON))) {
reason_len = reason->u.packed_hdrs.len;
} else if (reason->cause == CANCEL_REAS_RCVD_CANCEL &&
reason->u.e2e_cancel &&
!(Trans->flags & T_NO_E2E_CANCEL_REASON)) {
/* parse the entire cancel, to get all the Reason headers */
if(parse_headers(reason->u.e2e_cancel, HDR_EOH_F, 0)<0) {
LM_WARN("failed to parse headers\n");
}
for(hdr=get_hdr(reason->u.e2e_cancel, HDR_REASON_T), reas1=hdr;
hdr; hdr=next_sibling_hdr(hdr)) {
/* hdr->len includes CRLF */
reason_len += hdr->len;
reas_last=hdr;
}
} else if (unlikely(reason->cause < CANCEL_REAS_MIN))
LM_BUG("unhandled reason cause %d\n", reason->cause);
}
#endif /* CANCEL_REASON_SUPPORT */
invite_buf_end = invite_buf + invite_len;
s = invite_buf;
/* Allocate memory for the new message.
The new request will be smaller than the INVITE, so the same size is enough.
I just extend it with the length of new To HF to be sure.
Ugly, but we avoid lots of checks and memory allocations this way */
to_len = to ? to->len : 0;
#ifdef CANCEL_REASON_SUPPORT
cancel_buf_len = invite_len + to_len + reason_len;
#else
cancel_buf_len = invite_len + to_len;
#endif /* CANCEL_REASON_SUPPORT */
cancel_buf = shm_malloc(sizeof(char)*cancel_buf_len);
if (!cancel_buf)
{
LM_ERR("cannot allocate shared memory\n");
goto error;
}
d = cancel_buf;
/* method name + space */
append_str(d, method, method_len);
*d = ' ';
d++;
/* skip "INVITE " and copy the rest of the line including CRLF */
s += 7;
s1 = s;
s = eat_line(s, invite_buf_end - s);
append_str(d, s1, s - s1);
cenv = sr_cfgenv_get();
/* check every header field name,
we must exclude and modify some of the headers */
first_via = 1;
while (s < invite_buf_end) {
s1 = s;
if ((*s == '\n') || (*s == '\r')) {
/* end of SIP msg */
hf_type = HDR_EOH_T;
} else {
/* parse HF name */
s = lw_get_hf_name(s, invite_buf_end,
&hf_type);
}
switch(hf_type) {
case HDR_CSEQ_T:
/* find the method name and replace it */
while ((s < invite_buf_end)
&& ((*s == ':') || (*s == ' ') || (*s == '\t') ||
((*s >= '0') && (*s <= '9')))
) s++;
append_str(d, s1, s - s1);
append_str(d, method, method_len);
append_str(d, CRLF, CRLF_LEN);
s = lw_next_line(s, invite_buf_end);
break;
case HDR_VIA_T:
s = lw_next_line(s, invite_buf_end);
if (first_via) {
/* copy hf */
append_str(d, s1, s - s1);
first_via = 0;
} /* else skip this line, we need olny the first via */
break;
case HDR_TO_T:
if (to_len == 0) {
/* there is no To tag required, just copy paste
* the header */
s = lw_next_line(s, invite_buf_end);
append_str(d, s1, s - s1);
} else {
/* use the given To HF instead of the original one */
append_str(d, to->s, to->len);
/* move the pointer to the next line */
s = lw_next_line(s, invite_buf_end);
}
break;
case HDR_FROM_T:
case HDR_CALLID_T:
case HDR_ROUTE_T:
case HDR_MAXFORWARDS_T:
/* copy hf */
s = lw_next_line(s, invite_buf_end);
append_str(d, s1, s - s1);
break;
case HDR_REQUIRE_T:
case HDR_PROXYREQUIRE_T:
/* skip this line */
s = lw_next_line(s, invite_buf_end);
break;
case HDR_CONTENTLENGTH_T:
/* copy hf name with 0 value */
append_str(d, s1, s - s1);
append_str(d, ": 0" CRLF, 3 + CRLF_LEN);
/* move the pointer to the next line */
s = lw_next_line(s, invite_buf_end);
break;
case HDR_EOH_T:
/* end of SIP message found */
#ifdef CANCEL_REASON_SUPPORT
/* add reason if needed */
if (reason_len) {
/* if reason_len !=0, no need for any reason enabled
* checks */
if (likely(reason->cause > 0)) {
append_str(d, REASON_PREFIX, REASON_PREFIX_LEN);
code_len=ushort2sbuf(reason->cause, d,
cancel_buf_len-(int)(d-cancel_buf));
if (unlikely(code_len==0))
LM_BUG("not enough space to write reason code");
d+=code_len;
if (reason->u.text.s){
append_str(d, REASON_TEXT, REASON_TEXT_LEN);
*d='"'; d++;
append_str(d, reason->u.text.s,
reason->u.text.len);
*d='"'; d++;
}
append_str(d, CRLF, CRLF_LEN);
} else if (likely(reason->cause ==
CANCEL_REAS_PACKED_HDRS)) {
append_str(d, reason->u.packed_hdrs.s,
reason->u.packed_hdrs.len);
} else if (reason->cause == CANCEL_REAS_RCVD_CANCEL) {
for(hdr=reas1; hdr; hdr=next_sibling_hdr(hdr)) {
/* hdr->len includes CRLF */
append_str(d, hdr->name.s, hdr->len);
if (likely(hdr==reas_last))
break;
}
}
}
#endif /* CANCEL_REASON_SUPPORT */
/* final (end-of-headers) CRLF */
append_str(d, CRLF, CRLF_LEN);
*len = d - cancel_buf;
/* LOG(L_DBG, "DBG: build_local: %.*s\n", *len, cancel_buf); */
return cancel_buf;
default:
s = lw_next_line(s, invite_buf_end);
hadded = 0;
/* uac auth headers */
if(Trans->uas.request &&
(Trans->uas.request->msg_flags & FL_UAC_AUTH)) {
if(s1 + cenv->uac_cseq_auth.len + 2 < invite_buf_end) {
if(s1[cenv->uac_cseq_auth.len]==':'
&& strncmp(s1, cenv->uac_cseq_auth.s,
cenv->uac_cseq_auth.len)==0) {
hadded = 1;
append_str(d, s1, s - s1);
} else if(s1[cenv->uac_cseq_refresh.len]==':'
&& strncmp(s1, cenv->uac_cseq_refresh.s,
cenv->uac_cseq_refresh.len)==0) {
hadded = 1;
append_str(d, s1, s - s1);
}
}
}
if(likely(hadded==0)) {
if (cfg_get(tm, tm_cfg, ac_extra_hdrs).len
&& (s1 + cfg_get(tm, tm_cfg, ac_extra_hdrs).len < invite_buf_end)
&& (strncasecmp(s1,
cfg_get(tm, tm_cfg, ac_extra_hdrs).s,
cfg_get(tm, tm_cfg, ac_extra_hdrs).len) == 0)) {
append_str(d, s1, s - s1);
}
}
break;
}
}
/* HDR_EOH_T was not found in the buffer, the message is corrupt */
LM_ERR("HDR_EOH_T was not found\n");
shm_free(cancel_buf);
error:
LM_ERR("cannot build %.*s request\n", method_len, method);
return NULL;
}
