dahdi_pcap: Imported user space utility for managing pcap streams

This utility will export packet captures for channels in dahdi. It requires
CONFIG_DAHDI_MIRROR to be defined in dahdi-linux as it uses the unsupported
DAHDI_MIRROR ioctl interface.

Internal-Issue-ID: DAHTOOL-49
From: Torrey Searle <tsearle@gmail.com>
Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
Acked-by: Shaun Ruffell <sruffell@digium.com>

git-svn-id: http://svn.asterisk.org/svn/dahdi/tools/trunk@10293 a0bf4364-ded3-4de4-8d8a-66a801d63aff

2 files changed, 336 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index be30fee..dd7e2fb 100644
--- a/Makefile
+++ b/Makefile
@@ -176,6 +176,9 @@ $(LTZ_SO): $(LTZ_SO_OBJS)
 
 dahdi_cfg: $(LTZ_A)
 dahdi_cfg: LIBS+=-lm
+dahdi_pcap:
+	$(CC) $(CFLAGS) dahdi_pcap.c -lpcap -o $@ $<
+	
 
 fxstest: $(LTZ_SO)
 fxstest: LIBS+=-lm
@@ -345,6 +348,7 @@ clean:
 	rm -f core
 	rm -f dahdi_cfg-shared fxstest
 	rm -rf $(GENERATED_DOCS) *.asciidoc tonezones.txt
+	rm -f dahdi_pcap
 
 distclean: dist-clean
 
diff --git a/dahdi_pcap.c b/dahdi_pcap.c
new file mode 100644
index 0000000..f6fa7fe
--- /dev/null
+++ b/dahdi_pcap.c
@@ -0,0 +1,332 @@
+/*
+ * Capturing a pcap from the DAHDI interface
+ * 
+ * Copyright (C) 2011 Torrey Searle
+ * 
+ * ISDN support added by Horacio Peña 
+ * Command line cleanups by Sverker Abrahamsson
+ * 
+ * Requirements:
+ * - pcap development library
+ * - DAHDI_MIRROR ioctl which isn't enabled by default in dahdi-linux
+ *   To enable this unsupported feature, #define CONFIG_DAHDI_MIRROR
+ *   in dahdi-linux
+ * - To build this program call the 'make dahdi_pcap' target
+ */
+
+/*
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2 as published by the
+ * Free Software Foundation. See the LICENSE file included with
+ * this program for more details.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <dahdi/user.h>
+#include <sys/time.h>
+#include <time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <string.h>
+#include <pcap.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <sys/ioctl.h>
+#include <stdlib.h>
+#include <getopt.h>
+
+#define BLOCK_SIZE 512
+#define MAX_CHAN 16
+//char ETH_P_LAPD[2] = {0x00, 0x30};
+
+struct mtp2_phdr {
+        u_int8_t  sent;
+        u_int8_t  annex_a_used;
+        u_int16_t link_number;
+};
+
+
+struct lapd_sll_hdr {
+    u_int16_t sll_pkttype;    /* packet type */
+    u_int16_t sll_hatype;
+    u_int16_t sll_halen;
+    u_int8_t sll_addr[8];
+    u_int8_t sll_protocol[2];   /* protocol, should be ETH_P_LAPD */
+};
+
+
+struct chan_fds {
+	int rfd;
+	int tfd;
+	int chan_id;
+	int proto;
+	char tx_buf[BLOCK_SIZE * 4];
+	int tx_len;
+	char rx_buf[BLOCK_SIZE * 4];
+	int rx_len;
+};
+
+int make_mirror(long type, int chan)
+{
+	int res = 0;
+	int fd = 0;	
+	struct dahdi_bufferinfo bi;
+	fd = open("/dev/dahdi/pseudo", O_RDONLY);
+
+	memset(&bi, 0, sizeof(bi));
+        bi.txbufpolicy = DAHDI_POLICY_IMMEDIATE;
+        bi.rxbufpolicy = DAHDI_POLICY_IMMEDIATE;
+        bi.numbufs = 32;
+        bi.bufsize = BLOCK_SIZE;
+
+	ioctl(fd, DAHDI_SET_BUFINFO, &bi);
+
+	res = ioctl(fd, type, &chan);
+
+	if(res)
+	{
+		printf("error setting channel err=%d!\n", res);
+		return -1;
+	}
+
+	
+	return fd;
+}
+
+int log_packet(struct chan_fds * fd, char is_read, pcap_dumper_t * dump)
+{
+	unsigned char buf[BLOCK_SIZE * 4];
+	int res = 0;
+
+	struct pcap_pkthdr hdr;
+	struct mtp2_phdr * mtp2 = (struct mtp2_phdr *)buf;
+	struct lapd_sll_hdr * lapd = (struct lapd_sll_hdr *)buf;
+
+	unsigned char *dataptr = buf;
+	int datasize = sizeof(buf);
+
+	if(fd->proto == DLT_LINUX_LAPD)
+	{
+		dataptr += sizeof(struct lapd_sll_hdr);
+		datasize -= sizeof(struct lapd_sll_hdr);
+	}
+	else
+	{
+		dataptr += sizeof(struct mtp2_phdr);
+		datasize -= sizeof(struct mtp2_phdr);
+	}
+
+	memset(buf, 0, sizeof(buf));
+	if(is_read)
+	{
+		res = read(fd->rfd, dataptr, datasize);
+		if(fd->rx_len > 0 && res == fd->rx_len && !memcmp(fd->rx_buf, dataptr, res) )
+		{
+			//skipping dup
+			return 0;
+		}
+
+		memcpy(fd->rx_buf,  dataptr, res);
+		fd->rx_len = res;
+	}
+	else
+	{
+		res = read(fd->tfd, dataptr, datasize);
+		if(fd->tx_len > 0 && res == fd->tx_len && !memcmp(fd->tx_buf, dataptr, res) )
+		{
+			//skipping dup
+			return 0;
+		}
+
+		memcpy(fd->tx_buf,  dataptr, res);
+		fd->tx_len = res;
+	}
+
+	gettimeofday(&hdr.ts, NULL);
+
+	
+
+	
+	if(res > 0)
+	{
+		if(fd->proto == DLT_LINUX_LAPD)
+		{
+			hdr.caplen = res+sizeof(struct lapd_sll_hdr)-2;
+			hdr.len = res+sizeof(struct lapd_sll_hdr)-2;
+			
+			lapd->sll_pkttype = 3;
+			lapd->sll_hatype = 0;
+			lapd->sll_halen = res;
+	//                lapd->sll_addr = ???
+			lapd->sll_protocol[0] = 0x00;
+			lapd->sll_protocol[1] = 0x30;
+
+		}
+		else
+		{
+			hdr.caplen = res+sizeof(struct mtp2_phdr);
+			hdr.len = res+sizeof(struct mtp2_phdr);
+			
+			if(is_read)
+			{
+				mtp2->sent = 0;
+				mtp2->annex_a_used = 0;
+			}
+			else
+			{
+				mtp2->sent = 1;
+				mtp2->annex_a_used = 0;
+			}
+			mtp2->link_number = htons(fd->chan_id);
+		}
+		pcap_dump((u_char*)dump, &hdr, buf);
+		pcap_dump_flush(dump);
+	}
+	return 1;
+}
+
+void usage() 
+{
+	printf("Usage: dahdi_pcap [OPTIONS]\n");
+	printf("Capture packets from DAHDI channels to pcap file\n\n");
+	printf("Options:\n");
+	printf("  -p, --proto=[mtp2|lapd] The protocol to capture, default mtp2\n");
+	printf("  -c, --chan=<channels>   Comma separated list of channels to capture from, max %d. Mandatory\n", MAX_CHAN);
+	printf("  -f, --file=<filename>   The pcap file to capture to. Mandatory\n");
+	printf("  -h, --help              Display this text\n");
+}
+
+int main(int argc, char **argv)
+{
+	struct chan_fds chans[MAX_CHAN];
+	char *filename = NULL;
+	int num_chans = 0;
+	int max_fd = 0;
+	int proto = DLT_MTP2_WITH_PHDR;
+
+	int i;
+	int packetcount;
+	int c;
+
+	while (1) {
+		int option_index = 0;
+		static struct option long_options[] = {
+			{"proto", required_argument, 0, 'p'},
+			{"chan", required_argument, 0, 'c'},
+			{"file", required_argument, 0, 'f'},
+			{"help", 0, 0, 'h'},
+			{0, 0, 0, 0}
+		};
+
+		c = getopt_long(argc, argv, "p:c:f:?",
+			  long_options, &option_index);
+		if (c == -1)
+			break;
+
+		switch (c) {
+			case 'p':
+				// Protocol
+				if(strcasecmp("LAPD", optarg)==0)
+				{
+					proto = DLT_LINUX_LAPD;
+				}
+				else if(argc > 0 && strcasecmp("MTP2", argv[1])==0)
+				{
+					proto = DLT_MTP2_WITH_PHDR;
+				}
+				break;
+			case 'c':
+				// TODO Should it be possible to override protocol per channel?
+				// Channels, comma separated list
+				while(optarg != NULL && num_chans < MAX_CHAN)
+				{
+					int chan = atoi(strsep(&optarg, ","));
+
+
+					chans[num_chans].tfd = make_mirror(DAHDI_TXMIRROR, chan);
+					chans[num_chans].rfd = make_mirror(DAHDI_RXMIRROR, chan);
+					chans[num_chans].chan_id = chan;
+					chans[num_chans].proto = proto;
+
+					if(chans[num_chans].tfd > max_fd)
+					{
+						max_fd = chans[num_chans].tfd;
+					}
+					if(chans[num_chans].rfd > max_fd)
+					{
+						max_fd = chans[num_chans].rfd;
+					}
+
+					num_chans++;
+				}
+				max_fd++;
+				break;
+			case 'f':
+				// File to capture to
+				filename=optarg;
+				break;
+			case 'h':
+			default:
+				// Usage
+				usage();
+				exit(0);
+		  }
+	}
+	if((num_chans == 0) || (filename == NULL)) {
+		usage();
+		exit(0);
+	}
+	else
+	{
+		printf("Capturing protocol %s on channels ", (proto == DLT_MTP2_WITH_PHDR ? "mtp2":"lapd"));
+		for(i = 0; i < num_chans; i++)
+		{
+			printf("%d", chans[i].chan_id);
+			if(i<num_chans-1)
+			{
+				printf(", ");
+			}
+		}
+		printf(" to file %s\n", filename);
+	}
+
+	pcap_t * pcap = pcap_open_dead(chans[0].proto, BLOCK_SIZE*4);
+	pcap_dumper_t * dump = pcap_dump_open(pcap, filename);
+	
+	packetcount=0;
+	while(1)
+	{
+		fd_set rd_set;
+		FD_ZERO(&rd_set);
+		for(i = 0; i < num_chans; i++)
+		{
+			FD_SET(chans[i].tfd, &rd_set);
+			FD_SET(chans[i].rfd, &rd_set);
+		}
+
+		select(max_fd, &rd_set, NULL, NULL, NULL);
+
+		for(i = 0; i < num_chans; i++)
+		{
+			if(FD_ISSET(chans[i].rfd, &rd_set))
+			{
+				packetcount += log_packet(&chans[i], 1, dump);
+			}
+			if(FD_ISSET(chans[i].tfd, &rd_set))
+			{
+				packetcount += log_packet(&chans[i], 0, dump);
+			}
+		}
+		printf("Packets captured: %d\r", packetcount);
+		fflush(stdout);
+	}
+
+	return 0;
+}