From 437bf2b8b72f9d89422447c85b93f1c62af4bab1 Mon Sep 17 00:00:00 2001
From: Heikki Hannikainen <hessu@hes.iki.fi>
Date: Thu, 27 Jun 2013 08:28:49 +0300
Subject: [PATCH] IS2: additional deframing code

---
 src/aprsis2.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
 src/aprsis2.h |  1 +
 src/uplink.c  | 11 +++++++----
 src/worker.c  |  2 --
 4 files changed, 57 insertions(+), 7 deletions(-)

diff --git a/src/aprsis2.c b/src/aprsis2.c
index 3a29c66..8b45390 100644
--- a/src/aprsis2.c
+++ b/src/aprsis2.c
@@ -4,6 +4,7 @@
 #include "aprsis2.h"
 #include "aprsis2.pb-c.h"
 #include "version.h"
+#include "hlog.h"
 
 #define IS2_HEAD_LEN 4
 #define IS2_TAIL_LEN 1
@@ -40,7 +41,54 @@ int is2_out_server_signature(struct worker_t *self, struct client_t *c)
 	return 0;
 }
 
-int is2_data_in(struct worker_t *self, struct client_t *c)
+static int is2_unpack_server_signature(struct worker_t *self, struct client_t *c, void *buf, int len)
 {
 	return 0;
 }
+
+#define IS2_MINIMUM_FRAME_LEN 4 + 1 + 1
+#define IS2_MINIMUM_FRAME_CONTENT_LEN 4
+
+static int is2_deframe(struct worker_t *self, struct client_t *c, char *s, int len)
+{
+	if (len < IS2_MINIMUM_FRAME_LEN) {
+		hlog_packet(LOG_WARNING, s, len, "%s/%s: IS2: Too short frame wrapper (%d): ",
+			c->addr_rem, c->username, len);
+		return -1;
+	}
+	
+	uint32_t *ip = (uint32_t *)s;
+	int clen = ntohl(*ip);
+	
+	if (clen < IS2_MINIMUM_FRAME_CONTENT_LEN) {
+		hlog_packet(LOG_WARNING, s, len, "%s/%s: IS2: Too short frame content (%d): ",
+			c->addr_rem, c->username, clen);
+		return -1;
+	}
+	
+	if (IS2_HEAD_LEN + clen + IS2_TAIL_LEN > len) {
+		hlog_packet(LOG_WARNING, s, len, "%s/%s: IS2: Frame length points behind buffer end (%d): ",
+			c->addr_rem, c->username, clen);
+		return -1;
+	}
+	
+	if (s[IS2_HEAD_LEN + clen] != '\n') {
+		hlog_packet(LOG_WARNING, s, len, "%s/%s: IS2: Frame missing terminating LF: ",
+			c->addr_rem, c->username);
+		return -1;
+	}
+	
+	hlog_packet(LOG_DEBUG, s, len, "%s/%s: IS2: framing ok: ", c->addr_rem, c->username);
+	
+	is2_unpack_server_signature(self, c, s, len);
+	
+	return 0;
+}
+
+int is2_in_server_signature(struct worker_t *self, struct client_t *c, char *s, int len)
+{
+	/* this one comes through the CRLF deframing */
+	is2_deframe(self, c, s, len+1);
+	
+	return 0;
+}
diff --git a/src/aprsis2.h b/src/aprsis2.h
index 136530e..59c58da 100644
--- a/src/aprsis2.h
+++ b/src/aprsis2.h
@@ -5,6 +5,7 @@
 #include "worker.h"
 
 extern int is2_out_server_signature(struct worker_t *self, struct client_t *c);
+extern int is2_in_server_signature(struct worker_t *self, struct client_t *c, char *s, int len);
 
 #endif
 
diff --git a/src/uplink.c b/src/uplink.c
index 50ba217..90522a1 100644
--- a/src/uplink.c
+++ b/src/uplink.c
@@ -44,6 +44,8 @@
 #include "outgoing.h"
 #include "filter.h"
 #include "tls.h"
+#include "aprsis2.h"
+
 
 int uplink_reconfiguring;
 int uplink_shutting_down;
@@ -297,10 +299,6 @@ int uplink_login_handler(struct worker_t *self, struct client_t *c, int l4proto,
 	int argc;
 	char *argv[256];
 	
-	//if (is2_in_server_signature(self, c, l4proto, s, len)
-	
-	hlog_packet(LOG_INFO, s, len, "%s: Uplink server software: ", c->addr_rem);
-	
 #ifdef USE_SSL
 	if (c->ssl_con && c->ssl_con->validate) {
 		hlog(LOG_DEBUG, "%s/%s: Uplink: Validating TLS server cert against CA", c->addr_rem, c->username);
@@ -314,6 +312,11 @@ int uplink_login_handler(struct worker_t *self, struct client_t *c, int l4proto,
 	}
 #endif
 	
+	if (is2_in_server_signature(self, c, s, len))
+		return 0;
+	
+	hlog_packet(LOG_INFO, s, len, "%s: Uplink server software: ", c->addr_rem);
+	
 	/* parse to arguments */
 	/* make it null-terminated for our string processing */
 	char *e = s + len;
diff --git a/src/worker.c b/src/worker.c
index be2a5b9..c76a3fb 100644
--- a/src/worker.c
+++ b/src/worker.c
@@ -1285,8 +1285,6 @@ int client_postread(struct worker_t *self, struct client_t *c, int r)
 	return 0;
 }
 
-
-
 /*
  *	handle an event on an fd
  */