MFC r304572 (by bz):

  Remove the kernel optoion for IPSEC_FILTERTUNNEL, which was deprecated
  more than 7 years ago in favour of a sysctl in r192648.

MFC r305122:
  Remove redundant sanity checks from ipsec[46]_common_input_cb().

  This check already has been done in the each protocol callback.

MFC r309144,309174,309201 (by fabient):
  IPsec RFC6479 support for replay window sizes up to 2^32 - 32 packets.

  Since the previous algorithm, based on bit shifting, does not scale
  with large replay windows, the algorithm used here is based on
  RFC 6479: IPsec Anti-Replay Algorithm without Bit Shifting.
  The replay window will be fast to be updated, but will cost as many bits
  in RAM as its size.

  The previous implementation did not provide a lock on the replay window,
  which may lead to replay issues.

  Obtained from:	emeric.poupon@stormshield.eu
  Sponsored by:	Stormshield
  Differential Revision:	https://reviews.freebsd.org/D8468

MFC r309143,309146 (by fabient):
  In a dual processor system (2*6 cores) during IPSec throughput tests,
  we see a lot of contention on the arc4 lock, used to generate the IV
  of the ESP output packets.

  The idea of this patch is to split this mutex in order to reduce the
  contention on this lock.

  Update r309143 to prevent false sharing.

  Reviewed by:	delphij, markm, ache
  Approved by:	so
  Obtained from: emeric.poupon@stormshield.eu
  Sponsored by:	Stormshield
  Differential Revision:	https://reviews.freebsd.org/D8130

MFC r313330:
  Merge projects/ipsec into head/.

   Small summary
   -------------

  o Almost all IPsec releated code was moved into sys/netipsec.
  o New kernel modules added: ipsec.ko and tcpmd5.ko. New kernel
    option IPSEC_SUPPORT added. It enables support for loading
    and unloading of ipsec.ko and tcpmd5.ko kernel modules.
  o IPSEC_NAT_T option was removed. Now NAT-T support is enabled by
    default. The UDP_ENCAP_ESPINUDP_NON_IKE encapsulation type
    support was removed. Added TCP/UDP checksum handling for
    inbound packets that were decapsulated by transport mode SAs.
    setkey(8) modified to show run-time NAT-T configuration of SA.
  o New network pseudo interface if_ipsec(4) added. For now it is
    build as part of ipsec.ko module (or with IPSEC kernel).
    It implements IPsec virtual tunnels to create route-based VPNs.
  o The network stack now invokes IPsec functions using special
    methods. The only one header file <netipsec/ipsec_support.h>
    should be included to declare all the needed things to work
    with IPsec.
  o All IPsec protocols handlers (ESP/AH/IPCOMP protosw) were removed.
    Now these protocols are handled directly via IPsec methods.
  o TCP_SIGNATURE support was reworked to be more close to RFC.
  o PF_KEY SADB was reworked:
    - now all security associations stored in the single SPI namespace,
      and all SAs MUST have unique SPI.
    - several hash tables added to speed up lookups in SADB.
    - SADB now uses rmlock to protect access, and concurrent threads
      can do SA lookups in the same time.
    - many PF_KEY message handlers were reworked to reflect changes
      in SADB.
    - SADB_UPDATE message was extended to support new PF_KEY headers:
      SADB_X_EXT_NEW_ADDRESS_SRC and SADB_X_EXT_NEW_ADDRESS_DST. They
      can be used by IKE daemon to change SA addresses.
  o ipsecrequest and secpolicy structures were cardinally changed to
    avoid locking protection for ipsecrequest. Now we support
    only limited number (4) of bundled SAs, but they are supported
    for both INET and INET6.
  o INPCB security policy cache was introduced. Each PCB now caches
    used security policies to avoid SP lookup for each packet.
  o For inbound security policies added the mode, when the kernel does
    check for full history of applied IPsec transforms.
  o References counting rules for security policies and security
    associations were changed. The proper SA locking added into xform
    code.
  o xform code was also changed. Now it is possible to unregister xforms.
    tdb_xxx structures were changed and renamed to reflect changes in
    SADB/SPDB, and changed rules for locking and refcounting.

  Obtained from:	Yandex LLC
  Relnotes:	yes
  Sponsored by:	Yandex LLC
  Differential Revision:	https://reviews.freebsd.org/D9352

MFC r313331:
  Add removed headers into the ObsoleteFiles.inc.

MFC r313561 (by glebius):
  Move tcp_fields_to_net() static inline into tcp_var.h, just below its
  friend tcp_fields_to_host(). There is third party code that also uses
  this inline.

MFC r313697:
  Remove IPsec related PCB code from SCTP.

  The inpcb structure has inp_sp pointer that is initialized by
  ipsec_init_pcbpolicy() function. This pointer keeps strorage for IPsec
  security policies associated with a specific socket.
  An application can use IP_IPSEC_POLICY and IPV6_IPSEC_POLICY socket
  options to configure these security policies. Then ip[6]_output()
  uses inpcb pointer to specify that an outgoing packet is associated
  with some socket. And IPSEC_OUTPUT() method can use a security policy
  stored in the inp_sp. For inbound packet the protocol-specific input
  routine uses IPSEC_CHECK_POLICY() method to check that a packet conforms
  to inbound security policy configured in the inpcb.

  SCTP protocol doesn't specify inpcb for ip[6]_output() when it sends
  packets. Thus IPSEC_OUTPUT() method does not consider such packets as
  associated with some socket and can not apply security policies
  from inpcb, even if they are configured. Since IPSEC_CHECK_POLICY()
  method is called from protocol-specific input routine, it can specify
  inpcb pointer and associated with socket inbound policy will be
  checked. But there are two problems:
  1. Such check is asymmetric, becasue we can not apply security policy
  from inpcb for outgoing packet.
  2. IPSEC_CHECK_POLICY() expects that caller holds INPCB lock and
  access to inp_sp is protected. But for SCTP this is not correct,
  becasue SCTP uses own locks to protect inpcb.

  To fix these problems remove IPsec related PCB code from SCTP.
  This imply that IP_IPSEC_POLICY and IPV6_IPSEC_POLICY socket options
  will be not applicable to SCTP sockets. To be able correctly check
  inbound security policies for SCTP, mark its protocol header with
  the PR_LASTHDR flag.

  Differential Revision:	https://reviews.freebsd.org/D9538

MFC r313746:
  Add missing check to fix the build with IPSEC_SUPPORT and without MAC.

MFC r313805:
  Fix LINT build for powerpc.

  Build kernel modules support only when both IPSEC and TCP_SIGNATURE
  are not defined.

MFC r313922:
  For translated packets do not adjust UDP checksum if it is zero.

  In case when decrypted and decapsulated packet is an UDP datagram,
  check that its checksum is not zero before doing incremental checksum
  adjustment.

MFC r314339:
  Document that the size of AH ICV for HMAC-SHA2-NNN should be half of
  NNN bits as described in RFC4868.

  PR:		215978

MFC r314812:
  Introduce the concept of IPsec security policies scope.

  Currently are defined three scopes: global, ifnet, and pcb.
  Generic security policies that IKE daemon can add via PF_KEY interface
  or an administrator creates with setkey(8) utility have GLOBAL scope.
  Such policies can be applied by the kernel to outgoing packets and checked
  agains inbound packets after IPsec processing.
  Security policies created by if_ipsec(4) interfaces have IFNET scope.
  Such policies are applied to packets that are passed through if_ipsec(4)
  interface.
  And security policies created by application using setsockopt()
  IP_IPSEC_POLICY option have PCB scope. Such policies are applied to
  packets related to specific socket. Currently there is no way to list
  PCB policies via setkey(8) utility.

  Modify setkey(8) and libipsec(3) to be able distinguish the scope of
  security policies in the `setkey -DP` listing. Add two optional flags:
  '-t' to list only policies related to virtual *tunneling* interfaces,
  i.e. policies with IFNET scope, and '-g' to list only policies with GLOBAL
  scope. By default policies from all scopes are listed.

  To implement this PF_KEY's sadb_x_policy structure was modified.
  sadb_x_policy_reserved field is used to pass the policy scope from the
  kernel to userland. SADB_SPDDUMP message extended to support filtering
  by scope: sadb_msg_satype field is used to specify bit mask of requested
  scopes.

  For IFNET policies the sadb_x_policy_priority field of struct sadb_x_policy
  is used to pass if_ipsec's interface if_index to the userland. For GLOBAL
  policies sadb_x_policy_priority is used only to manage order of security
  policies in the SPDB. For IFNET policies it is not used, so it can be used
  to keep if_index.

  After this change the output of `setkey -DP` now looks like:
  # setkey -DPt
  0.0.0.0/0[any] 0.0.0.0/0[any] any
  	in ipsec
  	esp/tunnel/87.250.242.144-87.250.242.145/unique:145
  	spid=7 seq=3 pid=58025 scope=ifnet ifname=ipsec0
  	refcnt=1
  # setkey -DPg
  ::/0 ::/0 icmp6 135,0
  	out none
  	spid=5 seq=1 pid=872 scope=global
  	refcnt=1

  Obtained from:	Yandex LLC
  Sponsored by:	Yandex LLC
  Differential Revision:	https://reviews.freebsd.org/D9805

PR:		212018
Relnotes:	yes
Sponsored by:	Yandex LLC

1 files changed, 10 insertions, 359 deletions

diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index 662c435..4fd388b 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -114,15 +114,7 @@ __FBSDID("$FreeBSD$");
 #include <netinet/tcp_offload.h>
 #endif
 
-#ifdef IPSEC
-#include <netipsec/ipsec.h>
-#include <netipsec/xform.h>
-#ifdef INET6
-#include <netipsec/ipsec6.h>
-#endif
-#include <netipsec/key.h>
-#include <sys/syslog.h>
-#endif /*IPSEC*/
+#include <netipsec/ipsec_support.h>
 
 #include <machine/in_cksum.h>
 #include <sys/md5.h>
@@ -229,12 +221,6 @@ static int	tcp_soreceive_stream;
 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
     &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
 
-#ifdef TCP_SIGNATURE
-static int	tcp_sig_checksigs = 1;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, signature_verify_input, CTLFLAG_RW,
-    &tcp_sig_checksigs, 0, "Verify RFC2385 digests on inbound traffic");
-#endif
-
 VNET_DEFINE(uma_zone_t, sack_hole_zone);
 #define	V_sack_hole_zone		VNET(sack_hole_zone)
 
@@ -1049,12 +1035,11 @@ tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
 			to.to_tsecr = tp->ts_recent;
 			to.to_flags |= TOF_TS;
 		}
-#ifdef TCP_SIGNATURE
+#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
 		/* TCP-MD5 (RFC2385). */
 		if (tp->t_flags & TF_SIGNATURE)
 			to.to_flags |= TOF_SIGNATURE;
 #endif
-
 		/* Add the options. */
 		tlen += optlen = tcp_addoptions(&to, optp);
 
@@ -1110,10 +1095,13 @@ tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
 		nth->th_win = htons((u_short)win);
 	nth->th_urp = 0;
 
-#ifdef TCP_SIGNATURE
+#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
 	if (to.to_flags & TOF_SIGNATURE) {
-		tcp_signature_compute(m, 0, 0, optlen, to.to_signature,
-		    IPSEC_DIR_OUTBOUND);
+		if (!TCPMD5_ENABLED() ||
+		    TCPMD5_OUTPUT(m, nth, to.to_signature) != 0) {
+			m_freem(m);
+			return;
+		}
 	}
 #endif
 
@@ -2483,7 +2471,7 @@ tcp_maxseg(const struct tcpcb *tp)
 			optlen = TCPOLEN_TSTAMP_APPA;
 		else
 			optlen = 0;
-#ifdef TCP_SIGNATURE
+#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
 		if (tp->t_flags & TF_SIGNATURE)
 			optlen += PAD(TCPOLEN_SIGNATURE);
 #endif
@@ -2499,7 +2487,7 @@ tcp_maxseg(const struct tcpcb *tp)
 			optlen = PAD(TCPOLEN_MAXSEG);
 		if (tp->t_flags & TF_REQ_SCALE)
 			optlen += PAD(TCPOLEN_WINDOW);
-#ifdef TCP_SIGNATURE
+#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
 		if (tp->t_flags & TF_SIGNATURE)
 			optlen += PAD(TCPOLEN_SIGNATURE);
 #endif
@@ -2511,343 +2499,6 @@ tcp_maxseg(const struct tcpcb *tp)
 	return (tp->t_maxseg - optlen);
 }
 
-#ifdef IPSEC
-/* compute ESP/AH header size for TCP, including outer IP header. */
-size_t
-ipsec_hdrsiz_tcp(struct tcpcb *tp)
-{
-	struct inpcb *inp;
-	struct mbuf *m;
-	size_t hdrsiz;
-	struct ip *ip;
-#ifdef INET6
-	struct ip6_hdr *ip6;
-#endif
-	struct tcphdr *th;
-
-	if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL) ||
-		(!key_havesp(IPSEC_DIR_OUTBOUND)))
-		return (0);
-	m = m_gethdr(M_NOWAIT, MT_DATA);
-	if (!m)
-		return (0);
-
-#ifdef INET6
-	if ((inp->inp_vflag & INP_IPV6) != 0) {
-		ip6 = mtod(m, struct ip6_hdr *);
-		th = (struct tcphdr *)(ip6 + 1);
-		m->m_pkthdr.len = m->m_len =
-			sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
-		tcpip_fillheaders(inp, ip6, th);
-		hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
-	} else
-#endif /* INET6 */
-	{
-		ip = mtod(m, struct ip *);
-		th = (struct tcphdr *)(ip + 1);
-		m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
-		tcpip_fillheaders(inp, ip, th);
-		hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
-	}
-
-	m_free(m);
-	return (hdrsiz);
-}
-#endif /* IPSEC */
-
-#ifdef TCP_SIGNATURE
-/*
- * Callback function invoked by m_apply() to digest TCP segment data
- * contained within an mbuf chain.
- */
-static int
-tcp_signature_apply(void *fstate, void *data, u_int len)
-{
-
-	MD5Update(fstate, (u_char *)data, len);
-	return (0);
-}
-
-/*
- * XXX The key is retrieved from the system's PF_KEY SADB, by keying a
- * search with the destination IP address, and a 'magic SPI' to be
- * determined by the application. This is hardcoded elsewhere to 1179
-*/
-struct secasvar *
-tcp_get_sav(struct mbuf *m, u_int direction)
-{
-	union sockaddr_union dst;
-	struct secasvar *sav;
-	struct ip *ip;
-#ifdef INET6
-	struct ip6_hdr *ip6;
-	char ip6buf[INET6_ADDRSTRLEN];
-#endif
-
-	/* Extract the destination from the IP header in the mbuf. */
-	bzero(&dst, sizeof(union sockaddr_union));
-	ip = mtod(m, struct ip *);
-#ifdef INET6
-	ip6 = NULL;	/* Make the compiler happy. */
-#endif
-	switch (ip->ip_v) {
-#ifdef INET
-	case IPVERSION:
-		dst.sa.sa_len = sizeof(struct sockaddr_in);
-		dst.sa.sa_family = AF_INET;
-		dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ?
-		    ip->ip_src : ip->ip_dst;
-		break;
-#endif
-#ifdef INET6
-	case (IPV6_VERSION >> 4):
-		ip6 = mtod(m, struct ip6_hdr *);
-		dst.sa.sa_len = sizeof(struct sockaddr_in6);
-		dst.sa.sa_family = AF_INET6;
-		dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ?
-		    ip6->ip6_src : ip6->ip6_dst;
-		break;
-#endif
-	default:
-		return (NULL);
-		/* NOTREACHED */
-		break;
-	}
-
-	/* Look up an SADB entry which matches the address of the peer. */
-	sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI));
-	if (sav == NULL) {
-		ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__,
-		    (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) :
-#ifdef INET6
-			(ip->ip_v == (IPV6_VERSION >> 4)) ?
-			    ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) :
-#endif
-			"(unsupported)"));
-	}
-
-	return (sav);
-}
-
-/*
- * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
- *
- * Parameters:
- * m		pointer to head of mbuf chain
- * len		length of TCP segment data, excluding options
- * optlen	length of TCP segment options
- * buf		pointer to storage for computed MD5 digest
- * sav		pointer to security assosiation
- *
- * We do this over ip, tcphdr, segment data, and the key in the SADB.
- * When called from tcp_input(), we can be sure that th_sum has been
- * zeroed out and verified already.
- *
- * Releases reference to SADB key before return. 
- *
- * Return 0 if successful, otherwise return -1.
- *
- */
-int
-tcp_signature_do_compute(struct mbuf *m, int len, int optlen,
-    u_char *buf, struct secasvar *sav)
-{
-#ifdef INET
-	struct ippseudo ippseudo;
-#endif
-	MD5_CTX ctx;
-	int doff;
-	struct ip *ip;
-#ifdef INET
-	struct ipovly *ipovly;
-#endif
-	struct tcphdr *th;
-#ifdef INET6
-	struct ip6_hdr *ip6;
-	struct in6_addr in6;
-	uint32_t plen;
-	uint16_t nhdr;
-#endif
-	u_short savecsum;
-
-	KASSERT(m != NULL, ("NULL mbuf chain"));
-	KASSERT(buf != NULL, ("NULL signature pointer"));
-
-	/* Extract the destination from the IP header in the mbuf. */
-	ip = mtod(m, struct ip *);
-#ifdef INET6
-	ip6 = NULL;	/* Make the compiler happy. */
-#endif
-
-	MD5Init(&ctx);
-	/*
-	 * Step 1: Update MD5 hash with IP(v6) pseudo-header.
-	 *
-	 * XXX The ippseudo header MUST be digested in network byte order,
-	 * or else we'll fail the regression test. Assume all fields we've
-	 * been doing arithmetic on have been in host byte order.
-	 * XXX One cannot depend on ipovly->ih_len here. When called from
-	 * tcp_output(), the underlying ip_len member has not yet been set.
-	 */
-	switch (ip->ip_v) {
-#ifdef INET
-	case IPVERSION:
-		ipovly = (struct ipovly *)ip;
-		ippseudo.ippseudo_src = ipovly->ih_src;
-		ippseudo.ippseudo_dst = ipovly->ih_dst;
-		ippseudo.ippseudo_pad = 0;
-		ippseudo.ippseudo_p = IPPROTO_TCP;
-		ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) +
-		    optlen);
-		MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo));
-
-		th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip));
-		doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen;
-		break;
-#endif
-#ifdef INET6
-	/*
-	 * RFC 2385, 2.0  Proposal
-	 * For IPv6, the pseudo-header is as described in RFC 2460, namely the
-	 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero-
-	 * extended next header value (to form 32 bits), and 32-bit segment
-	 * length.
-	 * Note: Upper-Layer Packet Length comes before Next Header.
-	 */
-	case (IPV6_VERSION >> 4):
-		ip6 = mtod(m, struct ip6_hdr *);
-		in6 = ip6->ip6_src;
-		in6_clearscope(&in6);
-		MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
-		in6 = ip6->ip6_dst;
-		in6_clearscope(&in6);
-		MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
-		plen = htonl(len + sizeof(struct tcphdr) + optlen);
-		MD5Update(&ctx, (char *)&plen, sizeof(uint32_t));
-		nhdr = 0;
-		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
-		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
-		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
-		nhdr = IPPROTO_TCP;
-		MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
-
-		th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr));
-		doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen;
-		break;
-#endif
-	default:
-		KEY_FREESAV(&sav);
-		return (-1);
-		/* NOTREACHED */
-		break;
-	}
-
-
-	/*
-	 * Step 2: Update MD5 hash with TCP header, excluding options.
-	 * The TCP checksum must be set to zero.
-	 */
-	savecsum = th->th_sum;
-	th->th_sum = 0;
-	MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
-	th->th_sum = savecsum;
-
-	/*
-	 * Step 3: Update MD5 hash with TCP segment data.
-	 *         Use m_apply() to avoid an early m_pullup().
-	 */
-	if (len > 0)
-		m_apply(m, doff, len, tcp_signature_apply, &ctx);
-
-	/*
-	 * Step 4: Update MD5 hash with shared secret.
-	 */
-	MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth));
-	MD5Final(buf, &ctx);
-
-	key_sa_recordxfer(sav, m);
-	KEY_FREESAV(&sav);
-	return (0);
-}
-
-/*
- * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
- *
- * Return 0 if successful, otherwise return -1.
- */
-int
-tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen,
-    u_char *buf, u_int direction)
-{
-	struct secasvar *sav;
-
-	if ((sav = tcp_get_sav(m, direction)) == NULL)
-		return (-1);
-
-	return (tcp_signature_do_compute(m, len, optlen, buf, sav));
-}
-
-/*
- * Verify the TCP-MD5 hash of a TCP segment. (RFC2385)
- *
- * Parameters:
- * m		pointer to head of mbuf chain
- * len		length of TCP segment data, excluding options
- * optlen	length of TCP segment options
- * buf		pointer to storage for computed MD5 digest
- * direction	direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
- *
- * Return 1 if successful, otherwise return 0.
- */
-int
-tcp_signature_verify(struct mbuf *m, int off0, int tlen, int optlen,
-    struct tcpopt *to, struct tcphdr *th, u_int tcpbflag)
-{
-	char tmpdigest[TCP_SIGLEN];
-
-	if (tcp_sig_checksigs == 0)
-		return (1);
-	if ((tcpbflag & TF_SIGNATURE) == 0) {
-		if ((to->to_flags & TOF_SIGNATURE) != 0) {
-
-			/*
-			 * If this socket is not expecting signature but
-			 * the segment contains signature just fail.
-			 */
-			TCPSTAT_INC(tcps_sig_err_sigopt);
-			TCPSTAT_INC(tcps_sig_rcvbadsig);
-			return (0);
-		}
-
-		/* Signature is not expected, and not present in segment. */
-		return (1);
-	}
-
-	/*
-	 * If this socket is expecting signature but the segment does not
-	 * contain any just fail.
-	 */
-	if ((to->to_flags & TOF_SIGNATURE) == 0) {
-		TCPSTAT_INC(tcps_sig_err_nosigopt);
-		TCPSTAT_INC(tcps_sig_rcvbadsig);
-		return (0);
-	}
-	if (tcp_signature_compute(m, off0, tlen, optlen, &tmpdigest[0],
-	    IPSEC_DIR_INBOUND) == -1) {
-		TCPSTAT_INC(tcps_sig_err_buildsig);
-		TCPSTAT_INC(tcps_sig_rcvbadsig);
-		return (0);
-	}
-	
-	if (bcmp(to->to_signature, &tmpdigest[0], TCP_SIGLEN) != 0) {
-		TCPSTAT_INC(tcps_sig_rcvbadsig);
-		return (0);
-	}
-	TCPSTAT_INC(tcps_sig_rcvgoodsig);
-	return (1);
-}
-#endif /* TCP_SIGNATURE */
-
 static int
 sysctl_drop(SYSCTL_HANDLER_ARGS)
 {