From 8e581a3ebe71eedb41ac7a41538e6b1b2b391744 Mon Sep 17 00:00:00 2001
From: Daniel-Constantin Mierla <miconda@gmail.com>
Date: Sun, 2 Sep 2018 12:33:17 +0200
Subject: [PATCH] core: functions to apply changes and update internal sip msg
 buffer

---
 src/core/msg_translator.c | 103 ++++++++++++++++++++++++++++++++++++++
 src/core/msg_translator.h |  11 ++++
 2 files changed, 114 insertions(+)

diff --git a/src/core/msg_translator.c b/src/core/msg_translator.c
index f82d72c3cb7..6929b22e0fe 100644
--- a/src/core/msg_translator.c
+++ b/src/core/msg_translator.c
@@ -3176,3 +3176,106 @@ int build_sip_msg_from_buf(struct sip_msg *msg, char *buf, int len,
 	return 0;
 }
 
+/**
+ *
+ */
+int sip_msg_update_buffer(sip_msg_t *msg, str *obuf)
+{
+	sip_msg_t tmp;
+
+	if(obuf==NULL || obuf->s==NULL || obuf->len<=0) {
+		LM_ERR("invalid buffer parameter\n");
+		return -1;
+	}
+
+	if(obuf->len >= BUF_SIZE) {
+		LM_ERR("new buffer is too large (%d)\n", obuf->len);
+		return -1;
+	}
+	/* temporary copy */
+	memcpy(&tmp, msg, sizeof(sip_msg_t));
+
+	/* reset dst uri and path vector to avoid freeing - restored later */
+	if(msg->dst_uri.s != NULL) {
+		msg->dst_uri.s = NULL;
+		msg->dst_uri.len = 0;
+	}
+	if(msg->path_vec.s != NULL) {
+		msg->path_vec.s = NULL;
+		msg->path_vec.len = 0;
+	}
+
+	/* free old msg structure */
+	free_sip_msg(msg);
+	memset(msg, 0, sizeof(sip_msg_t));
+
+	/* restore msg fields */
+	msg->buf = tmp.buf;
+	msg->id = tmp.id;
+	msg->rcv = tmp.rcv;
+	msg->set_global_address = tmp.set_global_address;
+	msg->set_global_port = tmp.set_global_port;
+	msg->flags = tmp.flags;
+	msg->msg_flags = tmp.msg_flags;
+	msg->hash_index = tmp.hash_index;
+	msg->force_send_socket = tmp.force_send_socket;
+	msg->fwd_send_flags = tmp.fwd_send_flags;
+	msg->rpl_send_flags = tmp.rpl_send_flags;
+	msg->dst_uri = tmp.dst_uri;
+	msg->path_vec = tmp.path_vec;
+
+	memcpy(msg->buf, obuf->s, obuf->len);
+	msg->len = obuf->len;
+	msg->buf[msg->len] = '\0';
+
+	/* reparse the message */
+	LM_DBG("SIP message content updated - reparsing\n");
+	if(parse_msg(msg->buf, msg->len, msg) != 0) {
+		LM_ERR("parsing new sip message failed [[%.*s]]\n", msg->len, msg->buf);
+		/* exit config execution - sip_msg_t structure is no longer
+		 * valid/safe for config */
+		return 0;
+	}
+
+	return 1;
+}
+
+/**
+ *
+ */
+int sip_msg_apply_changes(sip_msg_t *msg)
+{
+	int ret;
+	dest_info_t dst;
+	str obuf;
+
+	if(msg->first_line.type != SIP_REPLY && get_route_type() != REQUEST_ROUTE) {
+		LM_ERR("invalid usage - not in request route or a reply\n");
+		return -1;
+	}
+
+	init_dest_info(&dst);
+	dst.proto = PROTO_UDP;
+	if(msg->first_line.type == SIP_REPLY) {
+		obuf.s = generate_res_buf_from_sip_res(
+				msg, (unsigned int *)&obuf.len, BUILD_NO_VIA1_UPDATE);
+	} else {
+		if(msg->msg_flags & FL_RR_ADDED) {
+			LM_ERR("cannot apply msg changes after adding record-route"
+				   " header - it breaks conditional 2nd header\n");
+			return -1;
+		}
+		obuf.s = build_req_buf_from_sip_req(msg, (unsigned int *)&obuf.len,
+				&dst,
+				BUILD_NO_PATH | BUILD_NO_LOCAL_VIA | BUILD_NO_VIA1_UPDATE);
+	}
+	if(obuf.s == NULL) {
+		LM_ERR("couldn't update msg buffer content\n");
+		return -1;
+	}
+	ret = sip_msg_update_buffer(msg, &obuf);
+	/* free new buffer - copied in the static buffer from old sip_msg_t */
+	pkg_free(obuf.s);
+
+	return ret;
+}
diff --git a/src/core/msg_translator.h b/src/core/msg_translator.h
index d95c89f5e46..b6360ce3ff3 100644
--- a/src/core/msg_translator.h
+++ b/src/core/msg_translator.h
@@ -180,4 +180,15 @@ void process_lumps( struct sip_msg* msg,
                     unsigned int* orig_offs,
                     struct dest_info* send_info,
                     int flag);
+
+/**
+ * set the internal buffer for sip msg with obuf and reparse
+ */
+int sip_msg_update_buffer(sip_msg_t *msg, str *obuf);
+
+/**
+ * apply changes to sip msg buffer and reparse
+ */
+int sip_msg_apply_changes(sip_msg_t *msg);
+
 #endif