File: mod_print.c

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/*
 * mod_print.c
 *
 * Copyright (c) 2001 Dug Song <dugsong@monkey.org>
 *
 * $Id: mod_print.c,v 1.7 2002/04/07 22:55:20 dugsong Exp $
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mod.h"
#include "pkt.h"

#define EXTRACT_16BITS(p)	((uint16_t)ntohs(*(uint16_t *)(p)))
#define EXTRACT_32BITS(p)	((uint32_t)ntohl(*(uint32_t *)(p)))

/* XXX - _print_* routines adapted from tcpdump */

static void
_print_icmp(u_char *p, int length)
{
	struct ip_hdr *ip;
	struct icmp_hdr *icmp;
	
	ip = (struct ip_hdr *)p;
	icmp = (struct icmp_hdr *)(p + (ip->ip_hl * 4));

	/* XXX - truncation? */
	printf("%s > %s:", ip_ntoa(&ip->ip_src), ip_ntoa(&ip->ip_dst));
	printf(" icmp: type %d code %d", icmp->icmp_type, icmp->icmp_code);
}

void
_print_tcp(unsigned char *p, int length)
{
	struct ip_hdr *ip;
	struct tcp_hdr *tcp;
	u_short sport, dport, win, urp;
	u_long seq, ack;
	int len, tcp_hl;
	register char ch;
	
	ip = (struct ip_hdr *)p;
	tcp = (struct tcp_hdr *)(p + (ip->ip_hl * 4));
	len = length - (ip->ip_hl * 4);
	
	if (len < TCP_HDR_LEN) {
		printf("truncated-tcp %d", len);
		return;
	}
	sport = ntohs(tcp->th_sport);
	dport = ntohs(tcp->th_dport);
	seq = ntohl(tcp->th_seq);
	ack = ntohl(tcp->th_ack);
	win = ntohs(tcp->th_win);
	urp = ntohs(tcp->th_urp);
	tcp_hl = tcp->th_off * 4;
	
	printf("%s.%d > %s.%d: ", ip_ntoa(&ip->ip_src), sport,
	    ip_ntoa(&ip->ip_dst), dport);
	
	if (tcp->th_flags & (TH_SYN|TH_FIN|TH_RST|TH_PUSH)) {
		if (tcp->th_flags & TH_SYN)	putchar('S');
		if (tcp->th_flags & TH_FIN)	putchar('F');
		if (tcp->th_flags & TH_RST)	putchar('R');
		if (tcp->th_flags & TH_PUSH)	putchar('P');
	} else
		putchar('.');
	
	if (tcp_hl > len) {
		printf(" [bad hdr length]");
		return;
	}
	len -= tcp_hl;
	
	if (len > 0 || tcp->th_flags & (TH_SYN | TH_FIN | TH_RST))
		printf(" %lu:%lu(%d)", seq, seq + len, len);
	
	if (tcp->th_flags & TH_ACK)
		printf(" ack %lu", ack);
	printf(" win %d", win);
	if (tcp->th_flags & TH_URG)
		printf(" urg %d", urp);
	
	/* Handle options. */
	if ((tcp_hl -= TCP_HDR_LEN) > 0) {
		register const u_char *cp;
		register int i, opt, len, datalen;
		
		cp = (const u_char *)tcp + TCP_HDR_LEN;
		putchar(' ');
		ch = '<';
		
		while (tcp_hl > 0) {
			putchar(ch);
			opt = *cp++;
			if (TCP_OPT_TYPEONLY(opt)) {
				len = 1;
			} else {
				len = *cp++;    /* total including type, len */
				if (len < 2 || len > tcp_hl)
					goto bad;
				--tcp_hl;         /* account for length byte */
			}
			--tcp_hl;           /* account for type byte */
			datalen = 0;
			
/* Bail if "l" bytes of data are not left or were not captured  */
#define LENCHECK(l) { if ((l) > tcp_hl) goto bad; }
			
			switch (opt) {
			case TCP_OPT_MSS:
				printf("mss");
				datalen = 2;
				LENCHECK(datalen);
				printf(" %u", EXTRACT_16BITS(cp));
				break;
			case TCP_OPT_EOL:
				printf("eol");
				break;
			case TCP_OPT_NOP:
				printf("nop");
				break;
			case TCP_OPT_WSCALE:
				printf("wscale");
				datalen = 1;
				LENCHECK(datalen);
				printf(" %u", *cp);
				break;
			case TCP_OPT_SACKOK:
				printf("sackOK");
				if (len != 2)
					printf("[len %d]", len);
				break;
			case TCP_OPT_SACK:
				datalen = len - 2;
				if ((datalen % 8) != 0 ||
				    !(tcp->th_flags & TH_ACK)) {
					printf("malformed sack ");
					printf("[len %d] ", datalen);
					break;
				}
				printf("sack %d ", datalen / 8);
				break;
			case TCP_OPT_ECHO:
				printf("echo");
				datalen = 4;
				LENCHECK(datalen);
				printf(" %u", EXTRACT_32BITS(cp));
				break;
			case TCP_OPT_ECHOREPLY:
				printf("echoreply");
				datalen = 4;
				LENCHECK(datalen);
				printf(" %u", EXTRACT_32BITS(cp));
				break;
			case TCP_OPT_TIMESTAMP:
				printf("timestamp");
				datalen = 8;
				LENCHECK(4);
				printf(" %u", EXTRACT_32BITS(cp));
				LENCHECK(datalen);
				printf(" %u", EXTRACT_32BITS(cp + 4));
				break;
			case TCP_OPT_CC:
				printf("cc");
				datalen = 4;
				LENCHECK(datalen);
				printf(" %u", EXTRACT_32BITS(cp));
				break;
			case TCP_OPT_CCNEW:
				printf("ccnew");
				datalen = 4;
				LENCHECK(datalen);
				printf(" %u", EXTRACT_32BITS(cp));
				break;
			case TCP_OPT_CCECHO:
				printf("ccecho");
				datalen = 4;
				LENCHECK(datalen);
				printf(" %u", EXTRACT_32BITS(cp));
				break;
			default:
				printf("opt-%d:", opt);
				datalen = len - 2;
				for (i = 0; i < datalen; ++i) {
					LENCHECK(i);
					printf("%02x", cp[i]);
				}
				break;
			}
			/* Account for data printed */
			cp += datalen;
			tcp_hl -= datalen;
			
			/* Check specification against observed length */
			++datalen;                /* option octet */
			if (!TCP_OPT_TYPEONLY(opt))
				++datalen;              /* size octet */
			if (datalen != len)
				printf("[len %d]", len);
			ch = ',';
			if (opt == TCP_OPT_EOL)
				break;
		}
		putchar('>');
	}
	return;
 bad:
	fputs("[bad opt]", stdout);
	if (ch != '\0')
		putchar('>');
	return;
}

static void
_print_udp(u_char *p, int length)
{
	struct ip_hdr *ip;
	struct udp_hdr *udp;
	
	ip = (struct ip_hdr *)p;
	udp = (struct udp_hdr *)(p + (ip->ip_hl * 4));

	/* XXX - truncation? */
	printf("%s.%d > %s.%d:", ip_ntoa(&ip->ip_src), ntohs(udp->uh_sport),
	    ip_ntoa(&ip->ip_dst), ntohs(udp->uh_dport));
	
	printf(" udp %d", ntohs(udp->uh_ulen) - UDP_HDR_LEN);
}

static void
_print_ip(u_char *p, int length)
{
	struct ip_hdr *ip;
	u_int ip_off, ip_hl, ip_len;
	
	ip = (struct ip_hdr *)p;
	
	if (length < IP_HDR_LEN) {
		printf("truncated-ip %d", length);
		return;
	}
	ip_hl = ip->ip_hl * 4;
	ip_len = ntohs(ip->ip_len);
	
	if (length < ip_len) {
		printf("truncated-ip - %d bytes missing!", ip_len - length);
		return;
	}
	ip_off = ntohs(ip->ip_off);
	
	/* Handle first fragment. */
	if ((ip_off & IP_OFFMASK) == 0) {
		switch (ip->ip_p) {
		case IP_PROTO_TCP:
			_print_tcp(p, ip_len);
			break;
		case IP_PROTO_UDP:
			_print_udp(p, ip_len);
			break;
		case IP_PROTO_ICMP:
			_print_icmp(p, ip_len);
			break;
		default:
			printf("%s > %s:", ip_ntoa(&ip->ip_src),
			    ip_ntoa(&ip->ip_dst));
			printf(" ip-proto-%d %d", ip->ip_p, ip_len);
			break;
		}
	}
	/* Handle more frags. */
	if (ip_off & (IP_MF|IP_OFFMASK)) {
		if (ip_off & IP_OFFMASK)
			printf("%s > %s:", ip_ntoa(&ip->ip_src),
			    ip_ntoa(&ip->ip_dst));
		printf(" (frag %d:%d@%d%s)", ntohs(ip->ip_id), ip_len - ip_hl,
		    (ip_off & IP_OFFMASK) << 3, (ip_off & IP_MF) ? "+" : "");
	} else if (ip_off & IP_DF)
		printf(" (DF)");
	
	if (ip->ip_tos)
		printf(" [tos 0x%x]", ip->ip_tos);
	if (ip->ip_ttl <= 1)
		printf(" [ttl %d]", ip->ip_ttl);
}

static char *
timerntoa(struct timeval *tv)
{
	static char buf[128];
	uint64_t usec;

	usec = (tv->tv_sec * 1000000) + tv->tv_usec;
	
	snprintf(buf, sizeof(buf), "%d.%03d ms",
	    (int)(usec / 1000), (int)(usec % 1000));
	
	return (buf);
}

int
print_apply(void *d, struct pktq *pktq)
{
	struct pkt *pkt;

	TAILQ_FOREACH(pkt, pktq, pkt_next) {
		_print_ip(pkt->pkt_eth_data, pkt->pkt_end - pkt->pkt_eth_data);
		if (timerisset(&pkt->pkt_ts))
			printf(" [delay %s]", timerntoa(&pkt->pkt_ts));
		printf("\n");
	}
	return (0);
}

struct mod mod_print = {
	"print",		/* name */
	"print",		/* usage */
	NULL,			/* init */
	print_apply,		/* apply */
	NULL			/* close */
};