#ifndef lint
static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.109 2003-11-16 09:36:39 guy Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.114 2004-04-26 06:17:31 itojun Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
#include "nameser.h"
+#ifdef HAVE_LIBCRYPTO
+#include <openssl/md5.h>
+
+static int tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
+ const u_char *data, int length, const u_char *rcvsig);
+#endif
+
static void print_tcp_rst_data(register const u_char *sp, u_int length);
#define MAX_RST_DATA_LEN 30
static int tcp_cksum(register const struct ip *ip,
register const struct tcphdr *tp,
- register int len)
+ register u_int len)
{
union phu {
struct phdr {
const u_int16_t *sp;
/* pseudo-header.. */
- phu.ph.len = htons(len); /* XXX */
+ phu.ph.len = htons((u_int16_t)len);
phu.ph.mbz = 0;
phu.ph.proto = IPPROTO_TCP;
memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
#ifdef INET6
static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp,
- int len)
+ u_int len)
{
- size_t i, tlen;
+ size_t i;
register const u_int16_t *sp;
u_int32_t sum;
union {
u_int16_t pa[20];
} phu;
- tlen = EXTRACT_16BITS(&ip6->ip6_plen) + sizeof(struct ip6_hdr) -
- ((const char *)tp - (const char*)ip6);
-
/* pseudo-header */
memset(&phu, 0, sizeof(phu));
phu.ph.ph_src = ip6->ip6_src;
phu.ph.ph_dst = ip6->ip6_dst;
- phu.ph.ph_len = htonl(tlen);
+ phu.ph.ph_len = htonl(len);
phu.ph.ph_nxt = IPPROTO_TCP;
sum = 0;
sp = (const u_int16_t *)tp;
- for (i = 0; i < (tlen & ~1); i += 2)
+ for (i = 0; i < (len & ~1); i += 2)
sum += *sp++;
- if (tlen & 1)
+ if (len & 1)
sum += htons((*(const u_int8_t *)sp) << 8);
while (sum > 0xffff)
u_int16_t sum, tcp_sum;
if (TTEST2(tp->th_sport, length)) {
sum = tcp_cksum(ip, tp, length);
+
+ (void)printf(", cksum 0x%04x",EXTRACT_16BITS(&tp->th_sum));
if (sum != 0) {
tcp_sum = EXTRACT_16BITS(&tp->th_sum);
- (void)printf(" [bad tcp cksum %x (->%x)!]",
- tcp_sum, in_cksum_shouldbe(tcp_sum, sum));
+ (void)printf(" (incorrect (-> 0x%04x),",in_cksum_shouldbe(tcp_sum, sum));
} else
- (void)printf(" [tcp sum ok]");
+ (void)printf(" (correct),");
}
}
#ifdef INET6
if (IP_V(ip) == 6 && ip6->ip6_plen && vflag && !fragmented) {
- int sum;
+ u_int16_t sum,tcp_sum;
if (TTEST2(tp->th_sport, length)) {
sum = tcp6_cksum(ip6, tp, length);
- if (sum != 0)
- (void)printf(" [bad tcp cksum %x!]", sum);
- else
- (void)printf(" [tcp sum ok]");
+ (void)printf(", cksum 0x%04x",EXTRACT_16BITS(&tp->th_sum));
+ if (sum != 0) {
+ tcp_sum = EXTRACT_16BITS(&tp->th_sum);
+ (void)printf(" (incorrect (-> 0x%04x),",in_cksum_shouldbe(tcp_sum, sum));
+ } else
+ (void)printf(" (correct),");
+
}
}
#endif
(void)printf(" %u", EXTRACT_32BITS(cp));
break;
+ case TCPOPT_SIGNATURE:
+ (void)printf("md5:");
+ datalen = TCP_SIGLEN;
+ LENCHECK(datalen);
+#ifdef HAVE_LIBCRYPTO
+ if (tcp_verify_signature(ip, tp,
+ bp + TH_OFF(tp) * 4, length, cp) == 0)
+ (void)printf("valid");
+ else
+ (void)printf("invalid");
+#else
+ for (i = 0; i < TCP_SIGLEN; ++i)
+ (void)printf("%02x", cp[i]);
+#endif
+ break;
+
default:
(void)printf("opt-%u:", opt);
datalen = len - 2;
}
putchar(']');
}
+
+#ifdef HAVE_LIBCRYPTO
+static int
+tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
+ const u_char *data, int length, const u_char *rcvsig)
+{
+ struct tcphdr tp1;
+ char sig[TCP_SIGLEN];
+ char zero_proto = 0;
+ MD5_CTX ctx;
+ u_int16_t savecsum, tlen;
+ struct ip6_hdr *ip6;
+ u_int32_t len32;
+ u_int8_t nxt;
+
+ tp1 = *tp;
+
+ if (tcpmd5secret == NULL)
+ return (-1);
+
+ MD5_Init(&ctx);
+ /*
+ * Step 1: Update MD5 hash with IP pseudo-header.
+ */
+ if (IP_V(ip) == 4) {
+ MD5_Update(&ctx, (char *)&ip->ip_src, sizeof(ip->ip_src));
+ MD5_Update(&ctx, (char *)&ip->ip_dst, sizeof(ip->ip_dst));
+ MD5_Update(&ctx, (char *)&zero_proto, sizeof(zero_proto));
+ MD5_Update(&ctx, (char *)&ip->ip_p, sizeof(ip->ip_p));
+ tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
+ tlen = htons(tlen);
+ MD5_Update(&ctx, (char *)&tlen, sizeof(tlen));
+ } else if (IP_V(ip) == 6) {
+ ip6 = (struct ip6_hdr *)ip;
+ MD5_Update(&ctx, (char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
+ MD5_Update(&ctx, (char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
+ len32 = htonl(ntohs(ip6->ip6_plen));
+ MD5_Update(&ctx, (char *)&len32, sizeof(len32));
+ nxt = 0;
+ MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
+ MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
+ MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
+ nxt = IPPROTO_TCP;
+ MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
+ } else
+ return (-1);
+
+ /*
+ * Step 2: Update MD5 hash with TCP header, excluding options.
+ * The TCP checksum must be set to zero.
+ */
+ savecsum = tp1.th_sum;
+ tp1.th_sum = 0;
+ MD5_Update(&ctx, (char *)&tp1, sizeof(struct tcphdr));
+ tp1.th_sum = savecsum;
+ /*
+ * Step 3: Update MD5 hash with TCP segment data, if present.
+ */
+ if (length > 0)
+ MD5_Update(&ctx, data, length);
+ /*
+ * Step 4: Update MD5 hash with shared secret.
+ */
+ MD5_Update(&ctx, tcpmd5secret, strlen(tcpmd5secret));
+ MD5_Final(sig, &ctx);
+
+ return (memcmp(rcvsig, sig, 16));
+}
+#endif /* HAVE_LIBCRYPTO */
projects / tcpdump / blobdiff