sip: Register log callback function with sofia-sip

sofia-sip allows applications to register a log backend function
which will be called every time the library wants to log something.

We register such a call-back and make it log using the libosmocore logging
framework.

The problem is that sofia-sip has its own log level management, and by
the time the message hits libosmocore, we don't know which log level we
shall use :(

Change-Id: Ib269b6b50f9d79bbd13acc43a626834921f05edb
Related: OS#3105

src/app.h

@@ -9,6 +9,7 @@ struct app_config {
 	struct {
 		const char *local_addr;
 		int local_port;
+		int sofia_log_level;
 
 		const char *remote_addr;
 		int remote_port;

src/main.c

@@ -126,7 +126,7 @@ int main(int argc, char **argv)
 
 
 	/* parsing and setup */
-
+	g_app.sip.sofia_log_level = 2;
 	handle_options(argc, argv);
 	rc = vty_read_config_file(config_file, NULL);
 	if (rc < 0) {

src/sip.c

@@ -27,6 +27,7 @@
 #include <osmocom/core/utils.h>
 
 #include <sofia-sip/sip_status.h>
+#include <sofia-sip/su_log.h>
 
 #include <talloc.h>
 
@@ -383,12 +384,24 @@ char *make_sip_uri(struct sip_agent *agent)
 				agent->app->sip.local_port);
 }
 
+/* http://sofia-sip.sourceforge.net/refdocs/debug_logs.html */
+static void sip_logger(void *stream, char const *fmt, va_list ap)
+{
+	/* this is ugly, as unfortunately sofia-sip does not pass the log level to
+	 * the log handler call-back function, so we have no clue what log level the
+	 * currently logged message was sent for :(  As a result, we can only use one
+	 * hard-coded LOGL_NOTICE here */
+	osmo_vlogp(DSIP, LOGL_NOTICE, "", 0, 0, fmt, ap);
+}
+
 void sip_agent_init(struct sip_agent *agent, struct app_config *app)
 {
 	agent->app = app;
 
 	su_init();
 	su_home_init(&agent->home);
+	su_log_redirect(su_log_default, &sip_logger, NULL);
+	su_log_redirect(su_log_global, &sip_logger, NULL);
 	agent->root = su_glib_root_create(NULL);
 	su_root_threading(agent->root, 0);
 }

src/vty.c

@@ -1,5 +1,6 @@
 /*
  * (C) 2016 by Holger Hans Peter Freyther
+ * (C) 2018 by Harald Welte <laforge@gnumonks.org>
  *
  * All Rights Reserved
  *
@@ -25,6 +26,8 @@
 
 #include <talloc.h>
 
+#include <sofia-sip/su_log.h>
+
 extern void *tall_mncc_ctx;
 
 struct app_config g_app;
@@ -88,6 +91,7 @@ static int config_write_sip(struct vty *vty)
 	vty_out(vty, "sip%s", VTY_NEWLINE);
 	vty_out(vty, " local %s %d%s", g_app.sip.local_addr, g_app.sip.local_port, VTY_NEWLINE);
 	vty_out(vty, " remote %s %d%s", g_app.sip.remote_addr, g_app.sip.remote_port, VTY_NEWLINE);
+	vty_out(vty, " sofia-sip log-level %d%s", g_app.sip.sofia_log_level, VTY_NEWLINE);
 	return CMD_SUCCESS;
 }
 
@@ -133,6 +137,19 @@ DEFUN(cfg_sip_remote_addr, cfg_sip_remote_addr_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_sip_sofia_log_level, cfg_sip_sofia_log_level_cmd,
+	"sofia-sip log-level <0-9>",
+	"sofia-sip library configuration\n"
+	"global log-level for sofia-sip\n"
+	"(0 = nothing, 9 = super-verbose)\n")
+{
+	g_app.sip.sofia_log_level = atoi(argv[0]);
+	su_log_set_level(su_log_default, g_app.sip.sofia_log_level);
+	su_log_set_level(su_log_global, g_app.sip.sofia_log_level);
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_mncc, cfg_mncc_cmd,
 	"mncc",
 	"MNCC\n")
@@ -302,6 +319,7 @@ void mncc_sip_vty_init(void)
 	install_node(&sip_node, config_write_sip);
 	install_element(SIP_NODE, &cfg_sip_local_addr_cmd);
 	install_element(SIP_NODE, &cfg_sip_remote_addr_cmd);
+	install_element(SIP_NODE, &cfg_sip_sofia_log_level_cmd);
 
 	install_element(CONFIG_NODE, &cfg_mncc_cmd);
 	install_node(&mncc_node, config_write_mncc);