Added a little packet parsing.

git-svn-id: http://repo.ham.fi/svn/aprsc/trunk@6 3ce903b1-3385-4e86-93cd-f9a4a239f7ac

src/Makefile

@@ -23,6 +23,7 @@ distclean: clean
 
 BITS = aprsc.o accept.o worker.o \
 	login.o incoming.o dupecheck.o outgoing.o \
+	parse_aprs.o \
 	config.o netlib.o xpoll.o \
 	cfgfile.o passcode.o \
 	rwlock.o hmalloc.o hlog.o \
@@ -36,9 +37,11 @@ aprsc.o:	aprsc.c hmalloc.h hlog.h config.h splay.h accept.h
 accept.o:	accept.c accept.h hmalloc.h hlog.h config.h netlib.h worker.h dupecheck.h
 worker.o:	worker.c worker.h hmalloc.h hlog.h config.h xpoll.h incoming.h outgoing.h
 login.o:	login.c login.h hmalloc.h hlog.h worker.h passcode.h incoming.h config.h
-incoming.o:	incoming.c incoming.h hmalloc.h hlog.h worker.h
+incoming.o:	incoming.c incoming.h hmalloc.h hlog.h worker.h parse_aprs.h
 outgoing.o:	outgoing.c outgoing.h hlog.h worker.h
 dupecheck.o:	dupecheck.c dupecheck.h hmalloc.h hlog.h worker.h
+parse_aprs.o:	parse_aprs.c parse_aprs.h hlog.h
+parse_aprs.h:	worker.h
 passcode.o:	passcode.c passcode.h
 xpoll.o:	xpoll.c xpoll.h hmalloc.h hlog.h
 netlib.o:	netlib.c netlib.h worker.h

src/incoming.c

@@ -10,6 +10,7 @@
 #include "incoming.h"
 #include "hmalloc.h"
 #include "hlog.h"
+#include "parse_aprs.h"
 
 /*
  *	Get a buffer for a packet
@@ -125,9 +126,63 @@ void incoming_flush(struct worker_t *self)
 
 int incoming_parse(struct worker_t *self, struct pbuf_t *pb)
 {
-	/* TODO: get lat/lon out of position packets */
+	char *src_end; /* pointer to the > after srccall */
+	char *path_start; /* pointer to the start of the path */
+	char *path_end; /* pointer to the : after the path */
+	char *packet_end; /* pointer to the end of the packet */
+	char *info_start; /* pointer to the beginning of the info */
+	char *info_end; /* end of the info */
+	char *dstcall_end; /* end of dstcall ([:,]) */
 	
-	return 0;
+	/* a packet looks like:
+	 * SRCCALL>DSTCALL,PATH,PATH:INFO\r\n
+	 * (we have normalized the \r\n by now)
+	 */
+	
+	packet_end = pb->data + pb->packet_len; /* for easier overflow checking */
+	
+	/* look for the '>' */
+	src_end = memchr(pb->data, '>', pb->packet_len < CALLSIGNLEN_MAX+1 ? pb->packet_len : CALLSIGNLEN_MAX+1);
+	if (!src_end)
+		return -1;
+	
+	path_start = src_end+1;
+	if (path_start >= packet_end)
+		return -1;
+	
+	if (src_end - pb->data > CALLSIGNLEN_MAX)
+		return -1; /* too long source callsign */
+	
+	/* look for the : */
+	path_end = memchr(path_start, ':', packet_end - path_start);
+	if (!path_end)
+		return -1;
+	
+	info_start = path_end+1;
+	if (info_start >= packet_end)
+		return -1;
+	
+	/* see that there is at least some data in the packet */
+	info_end = packet_end - 2;
+	if (info_end <= info_start)
+		return -1;
+	
+	/* look up end of dstcall */
+	/* the logic behind this is slightly uncertain. */
+	dstcall_end = path_start;
+	while (dstcall_end < path_end && *dstcall_end != ',' && *dstcall_end != ',' && *dstcall_end != '-')
+		dstcall_end++;
+	
+	if (dstcall_end - path_start > CALLSIGNLEN_MAX)
+		return -1; /* too long destination callsign */
+	
+	/* fill necessary info for parsing and dupe checking in the packet buffer */
+	pb->srccall_end = src_end;
+	pb->dstcall_end = dstcall_end;
+	pb->info_start = info_start;
+	
+	/* just try APRS parsing */
+	return parse_aprs(self, pb);
 }
 
 /*
@@ -137,6 +192,7 @@ int incoming_parse(struct worker_t *self, struct pbuf_t *pb)
 int incoming_handler(struct worker_t *self, struct client_t *c, char *s, int len)
 {
 	struct pbuf_t *pb;
+	int e;
 	
 	/* note: len does not include CRLF, it's reconstructed here... we accept
 	 * CR, LF or CRLF on input but make sure to use CRLF on output.
@@ -171,7 +227,16 @@ int incoming_handler(struct worker_t *self, struct client_t *c, char *s, int len
 	memcpy((void *)&pb->addr, (void *)&c->addr, c->addr_len);
 	
 	/* do some parsing */
-	incoming_parse(self, pb);
+	e = incoming_parse(self, pb);
+	if (e < 0) {
+		/* failed parsing */
+		fprintf(stderr, "Failed parsing (%d):\n", e);
+		fwrite(pb->data, len, 1, stderr);
+		fprintf(stderr, "\n");
+		
+		// TODO: return buffer pbuf_put(self, pb);
+		return 0;
+	}
 	
 	/* put the buffer in the thread's incoming queue */
 	pb->next = NULL;

src/parse_aprs.c

@@ -0,0 +1,9 @@
+
+#include "parse_aprs.h"
+#include "hlog.h"
+
+int parse_aprs(struct worker_t *self, struct pbuf_t *pb)
+{
+	
+	return 0;
+}

src/parse_aprs.h

@@ -0,0 +1,10 @@
+
+#ifndef PARSE_APRS_H
+#define PARSE_APRS_H
+
+#include "worker.h"
+#include "parse_aprs.h"
+
+extern int parse_aprs(struct worker_t *self, struct pbuf_t *pb);
+
+#endif

src/worker.h

@@ -17,6 +17,8 @@
 
 extern time_t now;	/* current time - updated by the main thread */
 
+#define CALLSIGNLEN_MAX 9
+
 /* packet length limiters and buffer sizes */
 #define PACKETLEN_MIN 4		/* minimum length for a valid APRS-IS packet: "A>B:" */
 #define PACKETLEN_MAX 600	/* max... arbitrary and not documented */
@@ -46,13 +48,17 @@ struct pbuf_t {
 	int packettype;		/* bitmask: one or more of T_* */
 	int flags;		/* bitmask: one or more of F_* */
 	
-	float lat; /* if the packet is PT_POSITION, latitude and longitude go here */
-	float lng;
-	
 	int packet_len;		/* the actual length of the packet, including CRLF */
 	int buf_len;		/* the length of this buffer */
 	char *data;		/* contains the whole packet, including CRLF, ready to transmit */
 	
+	char *srccall_end;	/* source callsign with SSID */
+	char *dstcall_end;	/* end of dest callsign SSID */
+	char *info_start;	/* pointer to start of info field */
+	
+	float lat; /* if the packet is PT_POSITION, latitude and longitude go here */
+	float lng;
+	
 	struct sockaddr addr;	/* where did we get it from (don't send it back) */
 };