| /*- |
| * Copyright (c) 2001 McAfee, Inc. |
| * Copyright (c) 2006 Andre Oppermann, Internet Business Solutions AG |
| * All rights reserved. |
| * |
| * This software was developed for the FreeBSD Project by Jonathan Lemon |
| * and McAfee Research, the Security Research Division of McAfee, Inc. under |
| * DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the |
| * DARPA CHATS research program. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include <sys/bsd_cdefs.h> |
| //__FBSDID("$FreeBSD$"); |
| |
| #include "bsd_opt_inet.h" |
| #include "bsd_opt_inet6.h" |
| #include "bsd_opt_ipsec.h" |
| |
| #include <sys/bsd_param.h> |
| #include <sys/bsd_systm.h> |
| #include <sys/bsd_kernel.h> |
| //baoyg//#include <sys/bsd_sysctl.h> |
| #include <sys/bsd_limits.h> |
| #include <sys/bsd_lock.h> |
| #include <sys/bsd_mutex.h> |
| #include <sys/bsd_malloc.h> |
| #include <sys/bsd_mbuf.h> |
| #include <sys/bsd_md5.h> |
| ////#include <sys/bsd_proc.h> /* for proc0 declaration */ |
| #include <sys/bsd_random.h> |
| #include <sys/bsd_socket.h> |
| #include <sys/bsd_socketvar.h> |
| #include <sys/bsd_syslog.h> |
| #include <sys/bsd_ucred.h> |
| |
| #include <vm/bsd_uma.h> |
| |
| #include <net/bsd_if.h> |
| #include <net/bsd_route.h> |
| #include <net/bsd_vnet.h> |
| |
| #include <netinet/bsd_in.h> |
| #include <netinet/bsd_in_systm.h> |
| #include <netinet/bsd_ip.h> |
| #include <netinet/bsd_in_var.h> |
| #include <netinet/bsd_in_pcb.h> |
| #include <netinet/bsd_ip_var.h> |
| #include <netinet/bsd_ip_options.h> |
| #ifdef INET6 |
| #include <netinet/bsd_ip6.h> |
| #include <netinet/bsd_icmp6.h> |
| #include <netinet6/bsd_nd6.h> |
| #include <netinet6/bsd_ip6_var.h> |
| #include <netinet6/bsd_in6_pcb.h> |
| #endif |
| #include <netinet/bsd_tcp.h> |
| #include <netinet/bsd_tcp_fsm.h> |
| #include <netinet/bsd_tcp_seq.h> |
| #include <netinet/bsd_tcp_timer.h> |
| #include <netinet/bsd_tcp_var.h> |
| #include <netinet/bsd_tcp_syncache.h> |
| #include <netinet/bsd_tcp_offload.h> |
| #ifdef INET6 |
| #include <netinet6/bsd_tcp6_var.h> |
| #endif |
| |
| #ifdef IPSEC |
| #include <netipsec/bsd_ipsec.h> |
| #ifdef INET6 |
| #include <netipsec/bsd_ipsec6.h> |
| #endif |
| #include <netipsec/bsd_key.h> |
| #endif /*IPSEC*/ |
| |
| #include <machine/bsd_in_cksum.h> |
| |
| #ifdef MAC |
| #include <security/mac/bsd_mac_framework.h> |
| #endif |
| |
| extern int bsd_hz; |
| extern int bsd_ticks; |
| |
| static VNET_DEFINE(struct tcp_syncache, tcp_syncache); |
| static VNET_DEFINE(int, tcp_syncookies); |
| static VNET_DEFINE(int, tcp_syncookiesonly); |
| VNET_DEFINE(int, tcp_sc_rst_sock_fail); |
| |
| #define V_tcp_syncache VNET(tcp_syncache) |
| #define V_tcp_syncookies VNET(tcp_syncookies) |
| #define V_tcp_syncookiesonly VNET(tcp_syncookiesonly) |
| /* |
| SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, syncookies, CTLFLAG_RW, |
| &VNET_NAME(tcp_syncookies), 0, |
| "Use TCP SYN cookies if the syncache overflows"); |
| |
| SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, syncookies_only, CTLFLAG_RW, |
| &VNET_NAME(tcp_syncookiesonly), 0, |
| "Use only TCP SYN cookies"); |
| */ |
| #ifdef TCP_OFFLOAD_DISABLE |
| #define TOEPCB_ISSET(sc) (0) |
| #else |
| #define TOEPCB_ISSET(sc) ((sc)->sc_toepcb != NULL) |
| #endif |
| |
| static void syncache_drop(struct syncache *, struct syncache_head *); |
| static void syncache_free(struct syncache *); |
| static void syncache_insert(struct syncache *, struct syncache_head *); |
| struct syncache *syncache_lookup(struct in_conninfo *, struct syncache_head **); |
| static int syncache_respond(struct syncache *); |
| static struct socket *syncache_socket(struct syncache *, struct socket *, |
| struct mbuf *m); |
| static void syncache_timeout(struct syncache *sc, struct syncache_head *sch, |
| int docallout); |
| static void syncache_timer(void *); |
| static void syncookie_generate(struct syncache_head *, struct syncache *, |
| u_int32_t *); |
| static struct syncache |
| *syncookie_lookup(struct in_conninfo *, struct syncache_head *, |
| struct syncache *, struct tcpopt *, struct tcphdr *, |
| struct socket *); |
| |
| /* |
| * Transmit the SYN,ACK fewer times than TCP_MAXRXTSHIFT specifies. |
| * 3 retransmits corresponds to a timeout of 3 * (1 + 2 + 4 + 8) == 45 seconds, |
| * the odds are that the user has given up attempting to connect by then. |
| */ |
| #define SYNCACHE_MAXREXMTS 3 |
| |
| /* Arbitrary values */ |
| #define TCP_SYNCACHE_HASHSIZE 512 |
| #define TCP_SYNCACHE_BUCKETLIMIT 30 |
| /* |
| SYSCTL_NODE(_net_inet_tcp, OID_AUTO, syncache, CTLFLAG_RW, 0, "TCP SYN cache"); |
| |
| SYSCTL_VNET_INT(_net_inet_tcp_syncache, OID_AUTO, bucketlimit, CTLFLAG_RDTUN, |
| &VNET_NAME(tcp_syncache.bucket_limit), 0, |
| "Per-bucket hash limit for syncache"); |
| |
| SYSCTL_VNET_INT(_net_inet_tcp_syncache, OID_AUTO, cachelimit, CTLFLAG_RDTUN, |
| &VNET_NAME(tcp_syncache.cache_limit), 0, |
| "Overall entry limit for syncache"); |
| |
| SYSCTL_VNET_INT(_net_inet_tcp_syncache, OID_AUTO, count, CTLFLAG_RD, |
| &VNET_NAME(tcp_syncache.cache_count), 0, |
| "Current number of entries in syncache"); |
| |
| SYSCTL_VNET_INT(_net_inet_tcp_syncache, OID_AUTO, hashsize, CTLFLAG_RDTUN, |
| &VNET_NAME(tcp_syncache.hashsize), 0, |
| "Size of TCP syncache hashtable"); |
| |
| SYSCTL_VNET_INT(_net_inet_tcp_syncache, OID_AUTO, rexmtlimit, CTLFLAG_RW, |
| &VNET_NAME(tcp_syncache.rexmt_limit), 0, |
| "Limit on SYN/ACK retransmissions"); |
| |
| SYSCTL_VNET_INT(_net_inet_tcp_syncache, OID_AUTO, rst_on_sock_fail, |
| CTLFLAG_RW, &VNET_NAME(tcp_sc_rst_sock_fail), 0, |
| "Send reset on socket allocation failure"); |
| */ |
| static MALLOC_DEFINE(M_SYNCACHE, "syncache", "TCP syncache"); |
| |
| #define SYNCACHE_HASH(inc, mask) \ |
| ((V_tcp_syncache.hash_secret ^ \ |
| (inc)->inc_faddr.s_addr ^ \ |
| ((inc)->inc_faddr.s_addr >> 16) ^ \ |
| (inc)->inc_fport ^ (inc)->inc_lport) & mask) |
| |
| #define SYNCACHE_HASH6(inc, mask) \ |
| ((V_tcp_syncache.hash_secret ^ \ |
| (inc)->inc6_faddr.s6_addr32[0] ^ \ |
| (inc)->inc6_faddr.s6_addr32[3] ^ \ |
| (inc)->inc_fport ^ (inc)->inc_lport) & mask) |
| |
| #define ENDPTS_EQ(a, b) ( \ |
| (a)->ie_fport == (b)->ie_fport && \ |
| (a)->ie_lport == (b)->ie_lport && \ |
| (a)->ie_faddr.s_addr == (b)->ie_faddr.s_addr && \ |
| (a)->ie_laddr.s_addr == (b)->ie_laddr.s_addr \ |
| ) |
| |
| #define ENDPTS6_EQ(a, b) (memcmp(a, b, sizeof(*a)) == 0) |
| |
| #define SCH_LOCK(sch) mtx_lock(&(sch)->sch_mtx) |
| #define SCH_UNLOCK(sch) mtx_unlock(&(sch)->sch_mtx) |
| #define SCH_LOCK_ASSERT(sch) mtx_assert(&(sch)->sch_mtx, MA_OWNED) |
| |
| /* |
| * Requires the syncache entry to be already removed from the bucket list. |
| */ |
| static void |
| syncache_free(struct syncache *sc) |
| { |
| |
| if (sc->sc_ipopts) |
| (void) m_free(sc->sc_ipopts); |
| //if (sc->sc_cred) |
| // crfree(sc->sc_cred); |
| #ifdef MAC |
| mac_syncache_destroy(&sc->sc_label); |
| #endif |
| |
| uma_zfree(V_tcp_syncache.zone, sc); |
| } |
| |
| void |
| syncache_init(void) |
| { |
| int i; |
| |
| V_tcp_syncookies = 1; |
| V_tcp_syncookiesonly = 0; |
| V_tcp_sc_rst_sock_fail = 1; |
| |
| V_tcp_syncache.cache_count = 0; |
| V_tcp_syncache.hashsize = TCP_SYNCACHE_HASHSIZE; |
| V_tcp_syncache.bucket_limit = TCP_SYNCACHE_BUCKETLIMIT; |
| V_tcp_syncache.rexmt_limit = SYNCACHE_MAXREXMTS; |
| V_tcp_syncache.hash_secret = arc4random(); |
| |
| // TUNABLE_INT_FETCH("net.inet.tcp.syncache.hashsize", |
| // &V_tcp_syncache.hashsize); |
| // TUNABLE_INT_FETCH("net.inet.tcp.syncache.bucketlimit", |
| // &V_tcp_syncache.bucket_limit); |
| if (!powerof2(V_tcp_syncache.hashsize) || |
| V_tcp_syncache.hashsize == 0) { |
| printf("WARNING: syncache hash size is not a power of 2.\n"); |
| V_tcp_syncache.hashsize = TCP_SYNCACHE_HASHSIZE; |
| } |
| V_tcp_syncache.hashmask = V_tcp_syncache.hashsize - 1; |
| |
| /* Set limits. */ |
| V_tcp_syncache.cache_limit = |
| V_tcp_syncache.hashsize * V_tcp_syncache.bucket_limit; |
| // TUNABLE_INT_FETCH("net.inet.tcp.syncache.cachelimit", |
| // &V_tcp_syncache.cache_limit); |
| |
| /* Allocate the hash table. */ |
| V_tcp_syncache.hashbase = bsd_malloc(V_tcp_syncache.hashsize * sizeof(struct syncache_head), M_SYNCACHE, M_WAITOK | M_ZERO); |
| |
| /* Initialize the hash buckets. */ |
| for (i = 0; i < V_tcp_syncache.hashsize; i++) { |
| #ifdef VIMAGE |
| V_tcp_syncache.hashbase[i].sch_vnet = curvnet; |
| #endif |
| TAILQ_INIT(&V_tcp_syncache.hashbase[i].sch_bucket); |
| mtx_init(&V_tcp_syncache.hashbase[i].sch_mtx, "tcp_sc_head", |
| NULL, MTX_DEF); |
| //callout_init_mtx(&V_tcp_syncache.hashbase[i].sch_timer, |
| // &V_tcp_syncache.hashbase[i].sch_mtx, 0); |
| //V_tcp_syncache.hashbase[i].sch_length = 0; |
| } |
| |
| /* Create the syncache entry zone. */ |
| V_tcp_syncache.zone = uma_zcreate("syncache", sizeof(struct syncache), |
| NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); |
| uma_zone_set_max(V_tcp_syncache.zone, V_tcp_syncache.cache_limit); |
| } |
| |
| #ifdef VIMAGE |
| void |
| syncache_destroy(void) |
| { |
| |
| /* XXX walk the cache, free remaining objects, stop timers */ |
| |
| uma_zdestroy(V_tcp_syncache.zone); |
| FREE(V_tcp_syncache.hashbase, M_SYNCACHE); |
| } |
| #endif |
| |
| /* |
| * Inserts a syncache entry into the specified bucket row. |
| * Locks and unlocks the syncache_head autonomously. |
| */ |
| static void |
| syncache_insert(struct syncache *sc, struct syncache_head *sch) |
| { |
| struct syncache *sc2; |
| |
| SCH_LOCK(sch); |
| |
| /* |
| * Make sure that we don't overflow the per-bucket limit. |
| * If the bucket is full, toss the oldest element. |
| */ |
| if (sch->sch_length >= V_tcp_syncache.bucket_limit) { |
| KASSERT(!TAILQ_EMPTY(&sch->sch_bucket), |
| ("sch->sch_length incorrect")); |
| sc2 = TAILQ_LAST(&sch->sch_bucket, sch_head); |
| syncache_drop(sc2, sch); |
| TCPSTAT_INC(tcps_sc_bucketoverflow); |
| } |
| |
| /* Put it into the bucket. */ |
| TAILQ_INSERT_HEAD(&sch->sch_bucket, sc, sc_hash); |
| sch->sch_length++; |
| |
| /* Reinitialize the bucket row's timer. */ |
| if (sch->sch_length == 1) |
| sch->sch_nextc = bsd_ticks + INT_MAX; |
| syncache_timeout(sc, sch, 1); |
| |
| SCH_UNLOCK(sch); |
| |
| V_tcp_syncache.cache_count++; |
| TCPSTAT_INC(tcps_sc_added); |
| } |
| |
| /* |
| * Remove and free entry from syncache bucket row. |
| * Expects locked syncache head. |
| */ |
| static void |
| syncache_drop(struct syncache *sc, struct syncache_head *sch) |
| { |
| |
| SCH_LOCK_ASSERT(sch); |
| |
| TAILQ_REMOVE(&sch->sch_bucket, sc, sc_hash); |
| sch->sch_length--; |
| |
| #ifndef TCP_OFFLOAD_DISABLE |
| if (sc->sc_tu) |
| sc->sc_tu->tu_syncache_event(TOE_SC_DROP, sc->sc_toepcb); |
| #endif |
| syncache_free(sc); |
| V_tcp_syncache.cache_count--; |
| } |
| |
| /* |
| * Engage/reengage time on bucket row. |
| */ |
| static void |
| syncache_timeout(struct syncache *sc, struct syncache_head *sch, int docallout) |
| { |
| sc->sc_rxttime = bsd_ticks + |
| TCPTV_RTOBASE * (tcp_backoff[sc->sc_rxmits]); |
| sc->sc_rxmits++; |
| if (TSTMP_LT(sc->sc_rxttime, sch->sch_nextc)) { |
| sch->sch_nextc = sc->sc_rxttime; |
| if (docallout) |
| callout_reset(&sch->sch_timer, sch->sch_nextc - bsd_ticks, |
| syncache_timer, (void *)sch); |
| } |
| } |
| |
| /* |
| * Walk the timer queues, looking for SYN,ACKs that need to be retransmitted. |
| * If we have retransmitted an entry the maximum number of times, expire it. |
| * One separate timer for each bucket row. |
| */ |
| static void |
| syncache_timer(void *xsch) |
| { |
| struct syncache_head *sch = (struct syncache_head *)xsch; |
| struct syncache *sc, *nsc; |
| int tick = bsd_ticks; |
| char *s; |
| |
| CURVNET_SET(sch->sch_vnet); |
| |
| /* NB: syncache_head has already been locked by the callout. */ |
| SCH_LOCK_ASSERT(sch); |
| |
| /* |
| * In the following cycle we may remove some entries and/or |
| * advance some timeouts, so re-initialize the bucket timer. |
| */ |
| sch->sch_nextc = tick + INT_MAX; |
| |
| TAILQ_FOREACH_SAFE(sc, &sch->sch_bucket, sc_hash, nsc) { |
| /* |
| * We do not check if the listen socket still exists |
| * and accept the case where the listen socket may be |
| * gone by the time we resend the SYN/ACK. We do |
| * not expect this to happens often. If it does, |
| * then the RST will be sent by the time the remote |
| * host does the SYN/ACK->ACK. |
| */ |
| if (TSTMP_GT(sc->sc_rxttime, tick)) { |
| if (TSTMP_LT(sc->sc_rxttime, sch->sch_nextc)) |
| sch->sch_nextc = sc->sc_rxttime; |
| continue; |
| } |
| if (sc->sc_rxmits > V_tcp_syncache.rexmt_limit) { |
| if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { |
| bsd_log(LOG_DEBUG, "%s; %s: Retransmits exhausted, " |
| "giving up and removing syncache entry\n", |
| s, __func__); |
| bsd_free(s, M_TCPLOG); |
| } |
| syncache_drop(sc, sch); |
| TCPSTAT_INC(tcps_sc_stale); |
| continue; |
| } |
| if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { |
| bsd_log(LOG_DEBUG, "%s; %s: Response timeout, " |
| "retransmitting (%u) SYN|ACK\n", |
| s, __func__, sc->sc_rxmits); |
| bsd_free(s, M_TCPLOG); |
| } |
| |
| (void) syncache_respond(sc); |
| TCPSTAT_INC(tcps_sc_retransmitted); |
| syncache_timeout(sc, sch, 0); |
| } |
| if (!TAILQ_EMPTY(&(sch)->sch_bucket)) |
| callout_reset(&(sch)->sch_timer, (sch)->sch_nextc - tick, |
| syncache_timer, (void *)(sch)); |
| CURVNET_RESTORE(); |
| } |
| |
| /* |
| * Find an entry in the syncache. |
| * Returns always with locked syncache_head plus a matching entry or NULL. |
| */ |
| struct syncache * |
| syncache_lookup(struct in_conninfo *inc, struct syncache_head **schp) |
| { |
| struct syncache *sc; |
| struct syncache_head *sch; |
| |
| #ifdef INET6 |
| if (inc->inc_flags & INC_ISIPV6) { |
| sch = &V_tcp_syncache.hashbase[ |
| SYNCACHE_HASH6(inc, V_tcp_syncache.hashmask)]; |
| *schp = sch; |
| |
| SCH_LOCK(sch); |
| |
| /* Circle through bucket row to find matching entry. */ |
| TAILQ_FOREACH(sc, &sch->sch_bucket, sc_hash) { |
| if (ENDPTS6_EQ(&inc->inc_ie, &sc->sc_inc.inc_ie)) |
| return (sc); |
| } |
| } else |
| #endif |
| { |
| sch = &V_tcp_syncache.hashbase[ |
| SYNCACHE_HASH(inc, V_tcp_syncache.hashmask)]; |
| *schp = sch; |
| |
| SCH_LOCK(sch); |
| |
| /* Circle through bucket row to find matching entry. */ |
| TAILQ_FOREACH(sc, &sch->sch_bucket, sc_hash) { |
| #ifdef INET6 |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) |
| continue; |
| #endif |
| if (ENDPTS_EQ(&inc->inc_ie, &sc->sc_inc.inc_ie)) |
| return (sc); |
| } |
| } |
| SCH_LOCK_ASSERT(*schp); |
| return (NULL); /* always returns with locked sch */ |
| } |
| |
| /* |
| * This function is called when we get a RST for a |
| * non-existent connection, so that we can see if the |
| * connection is in the syn cache. If it is, zap it. |
| */ |
| void |
| syncache_chkrst(struct in_conninfo *inc, struct tcphdr *th) |
| { |
| struct syncache *sc; |
| struct syncache_head *sch; |
| char *s = NULL; |
| |
| sc = syncache_lookup(inc, &sch); /* returns locked sch */ |
| SCH_LOCK_ASSERT(sch); |
| |
| /* |
| * Any RST to our SYN|ACK must not carry ACK, SYN or FIN flags. |
| * See RFC 793 page 65, section SEGMENT ARRIVES. |
| */ |
| if (th->th_flags & (TH_ACK|TH_SYN|TH_FIN)) { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: Spurious RST with ACK, SYN or " |
| "FIN flag set, segment ignored\n", s, __func__); |
| TCPSTAT_INC(tcps_badrst); |
| goto done; |
| } |
| |
| /* |
| * No corresponding connection was found in syncache. |
| * If syncookies are enabled and possibly exclusively |
| * used, or we are under memory pressure, a valid RST |
| * may not find a syncache entry. In that case we're |
| * done and no SYN|ACK retransmissions will happen. |
| * Otherwise the the RST was misdirected or spoofed. |
| */ |
| if (sc == NULL) { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: Spurious RST without matching " |
| "syncache entry (possibly syncookie only), " |
| "segment ignored\n", s, __func__); |
| TCPSTAT_INC(tcps_badrst); |
| goto done; |
| } |
| |
| /* |
| * If the RST bit is set, check the sequence number to see |
| * if this is a valid reset segment. |
| * RFC 793 page 37: |
| * In all states except SYN-SENT, all reset (RST) segments |
| * are validated by checking their SEQ-fields. A reset is |
| * valid if its sequence number is in the window. |
| * |
| * The sequence number in the reset segment is normally an |
| * echo of our outgoing acknowlegement numbers, but some hosts |
| * send a reset with the sequence number at the rightmost edge |
| * of our receive window, and we have to handle this case. |
| */ |
| if (SEQ_GEQ(th->th_seq, sc->sc_irs) && |
| SEQ_LEQ(th->th_seq, sc->sc_irs + sc->sc_wnd)) { |
| syncache_drop(sc, sch); |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: Our SYN|ACK was rejected, " |
| "connection attempt aborted by remote endpoint\n", |
| s, __func__); |
| TCPSTAT_INC(tcps_sc_reset); |
| } else { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: RST with invalid SEQ %u != " |
| "IRS %u (+WND %u), segment ignored\n", |
| s, __func__, th->th_seq, sc->sc_irs, sc->sc_wnd); |
| TCPSTAT_INC(tcps_badrst); |
| } |
| |
| done: |
| if (s != NULL) |
| bsd_free(s, M_TCPLOG); |
| SCH_UNLOCK(sch); |
| } |
| |
| void |
| syncache_badack(struct in_conninfo *inc) |
| { |
| struct syncache *sc; |
| struct syncache_head *sch; |
| |
| sc = syncache_lookup(inc, &sch); /* returns locked sch */ |
| SCH_LOCK_ASSERT(sch); |
| if (sc != NULL) { |
| syncache_drop(sc, sch); |
| TCPSTAT_INC(tcps_sc_badack); |
| } |
| SCH_UNLOCK(sch); |
| } |
| |
| void |
| syncache_unreach(struct in_conninfo *inc, struct tcphdr *th) |
| { |
| struct syncache *sc; |
| struct syncache_head *sch; |
| |
| sc = syncache_lookup(inc, &sch); /* returns locked sch */ |
| SCH_LOCK_ASSERT(sch); |
| if (sc == NULL) |
| goto done; |
| |
| /* If the sequence number != sc_iss, then it's a bogus ICMP msg */ |
| if (ntohl(th->th_seq) != sc->sc_iss) |
| goto done; |
| |
| /* |
| * If we've rertransmitted 3 times and this is our second error, |
| * we remove the entry. Otherwise, we allow it to continue on. |
| * This prevents us from incorrectly nuking an entry during a |
| * spurious network outage. |
| * |
| * See tcp_notify(). |
| */ |
| if ((sc->sc_flags & SCF_UNREACH) == 0 || sc->sc_rxmits < 3 + 1) { |
| sc->sc_flags |= SCF_UNREACH; |
| goto done; |
| } |
| syncache_drop(sc, sch); |
| TCPSTAT_INC(tcps_sc_unreach); |
| done: |
| SCH_UNLOCK(sch); |
| } |
| |
| /* |
| * Build a new TCP socket structure from a syncache entry. |
| */ |
| static struct socket * |
| syncache_socket(struct syncache *sc, struct socket *lso, struct mbuf *m) |
| { |
| struct inpcb *inp = NULL; |
| struct socket *so; |
| struct tcpcb *tp; |
| char *s; |
| |
| INP_INFO_WLOCK_ASSERT(&V_tcbinfo); |
| |
| /* |
| * Ok, create the full blown connection, and set things up |
| * as they would have been set up if we had created the |
| * connection when the SYN arrived. If we can't create |
| * the connection, abort it. |
| */ |
| so = sonewconn(lso, SS_ISCONNECTED); |
| if (so == NULL) { |
| /* |
| * Drop the connection; we will either send a RST or |
| * have the peer retransmit its SYN again after its |
| * RTO and try again. |
| */ |
| TCPSTAT_INC(tcps_listendrop); |
| if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { |
| bsd_log(LOG_DEBUG, "%s; %s: Socket create failed " |
| "due to limits or memory shortage\n", |
| s, __func__); |
| bsd_free(s, M_TCPLOG); |
| } |
| goto abort2; |
| } |
| #ifdef MAC |
| mac_socketpeer_set_from_mbuf(m, so); |
| #endif |
| |
| inp = sotoinpcb(so); |
| inp->inp_inc.inc_fibnum = so->so_fibnum; |
| INP_WLOCK(inp); |
| |
| /* Insert new socket into PCB hash list. */ |
| inp->inp_inc.inc_flags = sc->sc_inc.inc_flags; |
| #ifdef INET6 |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) { |
| inp->in6p_laddr = sc->sc_inc.inc6_laddr; |
| } else { |
| inp->inp_vflag &= ~INP_IPV6; |
| inp->inp_vflag |= INP_IPV4; |
| #endif |
| inp->inp_laddr = sc->sc_inc.inc_laddr; |
| #ifdef INET6 |
| } |
| #endif |
| inp->inp_lport = sc->sc_inc.inc_lport; |
| if (in_pcbinshash(inp) != 0) { |
| /* |
| * Undo the assignments above if we failed to |
| * put the PCB on the hash lists. |
| */ |
| #ifdef INET6 |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) |
| inp->in6p_laddr = in6addr_any; |
| else |
| #endif |
| inp->inp_laddr.s_addr = INADDR_ANY; |
| inp->inp_lport = 0; |
| goto abort; |
| } |
| #ifdef IPSEC |
| /* Copy old policy into new socket's. */ |
| if (ipsec_copy_policy(sotoinpcb(lso)->inp_sp, inp->inp_sp)) |
| printf("syncache_socket: could not copy policy\n"); |
| #endif |
| #ifdef INET6 |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) { |
| struct inpcb *oinp = sotoinpcb(lso); |
| struct in6_addr laddr6; |
| struct sockaddr_in6 sin6; |
| /* |
| * Inherit socket options from the listening socket. |
| * Note that in6p_inputopts are not (and should not be) |
| * copied, since it stores previously received options and is |
| * used to detect if each new option is different than the |
| * previous one and hence should be passed to a user. |
| * If we copied in6p_inputopts, a user would not be able to |
| * receive options just after calling the accept system call. |
| */ |
| inp->inp_flags |= oinp->inp_flags & INP_CONTROLOPTS; |
| if (oinp->in6p_outputopts) |
| inp->in6p_outputopts = |
| ip6_copypktopts(oinp->in6p_outputopts, M_NOWAIT); |
| |
| sin6.sin6_family = AF_INET6; |
| sin6.sin6_len = sizeof(sin6); |
| sin6.sin6_addr = sc->sc_inc.inc6_faddr; |
| sin6.sin6_port = sc->sc_inc.inc_fport; |
| sin6.sin6_flowinfo = sin6.sin6_scope_id = 0; |
| laddr6 = inp->in6p_laddr; |
| if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) |
| inp->in6p_laddr = sc->sc_inc.inc6_laddr; |
| if (in6_pcbconnect(inp, (struct sockaddr *)&sin6, |
| thread0.td_ucred)) { |
| inp->in6p_laddr = laddr6; |
| goto abort; |
| } |
| /* Override flowlabel from in6_pcbconnect. */ |
| inp->inp_flow &= ~IPV6_FLOWLABEL_MASK; |
| inp->inp_flow |= sc->sc_flowlabel; |
| } else |
| #endif |
| { |
| struct in_addr laddr; |
| struct sockaddr_in sin; |
| |
| inp->inp_options = (m) ? ip_srcroute(m) : NULL; |
| |
| if (inp->inp_options == NULL) { |
| inp->inp_options = sc->sc_ipopts; |
| sc->sc_ipopts = NULL; |
| } |
| |
| sin.sin_family = AF_INET; |
| sin.sin_len = sizeof(sin); |
| sin.sin_addr = sc->sc_inc.inc_faddr; |
| sin.sin_port = sc->sc_inc.inc_fport; |
| bzero((caddr_t)sin.sin_zero, sizeof(sin.sin_zero)); |
| laddr = inp->inp_laddr; |
| if (inp->inp_laddr.s_addr == INADDR_ANY) |
| inp->inp_laddr = sc->sc_inc.inc_laddr; |
| if (in_pcbconnect(inp, (struct sockaddr *)&sin, |
| NULL/*thread0.td_ucred*/)) { |
| inp->inp_laddr = laddr; |
| goto abort; |
| } |
| } |
| tp = intotcpcb(inp); |
| tp->t_state = TCPS_SYN_RECEIVED; |
| tp->iss = sc->sc_iss; |
| tp->irs = sc->sc_irs; |
| tcp_rcvseqinit(tp); |
| tcp_sendseqinit(tp); |
| tp->snd_wl1 = sc->sc_irs; |
| tp->snd_max = tp->iss + 1; |
| tp->snd_nxt = tp->iss + 1; |
| tp->rcv_up = sc->sc_irs + 1; |
| tp->rcv_wnd = sc->sc_wnd; |
| tp->rcv_adv += tp->rcv_wnd; |
| tp->last_ack_sent = tp->rcv_nxt; |
| |
| tp->t_flags = sototcpcb(lso)->t_flags & (TF_NOPUSH|TF_NODELAY); |
| if (sc->sc_flags & SCF_NOOPT) |
| tp->t_flags |= TF_NOOPT; |
| else { |
| if (sc->sc_flags & SCF_WINSCALE) { |
| tp->t_flags |= TF_REQ_SCALE|TF_RCVD_SCALE; |
| tp->snd_scale = sc->sc_requested_s_scale; |
| tp->request_r_scale = sc->sc_requested_r_scale; |
| } |
| if (sc->sc_flags & SCF_TIMESTAMP) { |
| tp->t_flags |= TF_REQ_TSTMP|TF_RCVD_TSTMP; |
| tp->ts_recent = sc->sc_tsreflect; |
| tp->ts_recent_age = bsd_ticks; |
| tp->ts_offset = sc->sc_tsoff; |
| } |
| #ifdef TCP_SIGNATURE |
| if (sc->sc_flags & SCF_SIGNATURE) |
| tp->t_flags |= TF_SIGNATURE; |
| #endif |
| if (sc->sc_flags & SCF_SACK) |
| tp->t_flags |= TF_SACK_PERMIT; |
| } |
| |
| if (sc->sc_flags & SCF_ECN) |
| tp->t_flags |= TF_ECN_PERMIT; |
| |
| /* |
| * Set up MSS and get cached values from tcp_hostcache. |
| * This might overwrite some of the defaults we just set. |
| */ |
| tcp_mss(tp, sc->sc_peer_mss); |
| |
| /* |
| * If the SYN,ACK was retransmitted, reset cwnd to 1 segment. |
| */ |
| if (sc->sc_rxmits) |
| tp->snd_cwnd = tp->t_maxseg; |
| tcp_timer_activate(tp, TT_KEEP, tcp_keepinit); |
| |
| INP_WUNLOCK(inp); |
| |
| TCPSTAT_INC(tcps_accepts); |
| return (so); |
| |
| abort: |
| INP_WUNLOCK(inp); |
| abort2: |
| if (so != NULL) |
| soabort(so); |
| return (NULL); |
| } |
| |
| /* |
| * This function gets called when we receive an ACK for a |
| * socket in the LISTEN state. We look up the connection |
| * in the syncache, and if its there, we pull it out of |
| * the cache and turn it into a full-blown connection in |
| * the SYN-RECEIVED state. |
| */ |
| int |
| syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th, |
| struct socket **lsop, struct mbuf *m) |
| { |
| struct syncache *sc; |
| struct syncache_head *sch; |
| struct syncache scs; |
| char *s; |
| |
| /* |
| * Global TCP locks are held because we manipulate the PCB lists |
| * and create a new socket. |
| */ |
| INP_INFO_WLOCK_ASSERT(&V_tcbinfo); |
| KASSERT((th->th_flags & (TH_RST|TH_ACK|TH_SYN)) == TH_ACK, |
| ("%s: can handle only ACK", __func__)); |
| |
| sc = syncache_lookup(inc, &sch); /* returns locked sch */ |
| SCH_LOCK_ASSERT(sch); |
| if (sc == NULL) { |
| /* |
| * There is no syncache entry, so see if this ACK is |
| * a returning syncookie. To do this, first: |
| * A. See if this socket has had a syncache entry dropped in |
| * the past. We don't want to accept a bogus syncookie |
| * if we've never received a SYN. |
| * B. check that the syncookie is valid. If it is, then |
| * cobble up a fake syncache entry, and return. |
| */ |
| if (!V_tcp_syncookies) { |
| SCH_UNLOCK(sch); |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: Spurious ACK, " |
| "segment rejected (syncookies disabled)\n", |
| s, __func__); |
| goto failed; |
| } |
| bzero(&scs, sizeof(scs)); |
| sc = syncookie_lookup(inc, sch, &scs, to, th, *lsop); |
| SCH_UNLOCK(sch); |
| if (sc == NULL) { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: Segment failed " |
| "SYNCOOKIE authentication, segment rejected " |
| "(probably spoofed)\n", s, __func__); |
| goto failed; |
| } |
| } else { |
| /* Pull out the entry to unlock the bucket row. */ |
| TAILQ_REMOVE(&sch->sch_bucket, sc, sc_hash); |
| sch->sch_length--; |
| V_tcp_syncache.cache_count--; |
| SCH_UNLOCK(sch); |
| } |
| |
| /* |
| * Segment validation: |
| * ACK must match our initial sequence number + 1 (the SYN|ACK). |
| */ |
| if (th->th_ack != sc->sc_iss + 1 && !TOEPCB_ISSET(sc)) { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: ACK %u != ISS+1 %u, segment " |
| "rejected\n", s, __func__, th->th_ack, sc->sc_iss); |
| goto failed; |
| } |
| |
| /* |
| * The SEQ must fall in the window starting at the received |
| * initial receive sequence number + 1 (the SYN). |
| */ |
| if ((SEQ_LEQ(th->th_seq, sc->sc_irs) || |
| SEQ_GT(th->th_seq, sc->sc_irs + sc->sc_wnd)) && |
| !TOEPCB_ISSET(sc)) { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: SEQ %u != IRS+1 %u, segment " |
| "rejected\n", s, __func__, th->th_seq, sc->sc_irs); |
| goto failed; |
| } |
| |
| if (!(sc->sc_flags & SCF_TIMESTAMP) && (to->to_flags & TOF_TS)) { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: Timestamp not expected, " |
| "segment rejected\n", s, __func__); |
| goto failed; |
| } |
| /* |
| * If timestamps were negotiated the reflected timestamp |
| * must be equal to what we actually sent in the SYN|ACK. |
| */ |
| if ((to->to_flags & TOF_TS) && to->to_tsecr != sc->sc_ts && |
| !TOEPCB_ISSET(sc)) { |
| if ((s = tcp_log_addrs(inc, th, NULL, NULL))) |
| bsd_log(LOG_DEBUG, "%s; %s: TSECR %u != TS %u, " |
| "segment rejected\n", |
| s, __func__, to->to_tsecr, sc->sc_ts); |
| goto failed; |
| } |
| |
| *lsop = syncache_socket(sc, *lsop, m); |
| |
| if (*lsop == NULL) |
| TCPSTAT_INC(tcps_sc_aborted); |
| else |
| TCPSTAT_INC(tcps_sc_completed); |
| |
| /* how do we find the inp for the new socket? */ |
| if (sc != &scs) |
| syncache_free(sc); |
| return (1); |
| failed: |
| if (sc != NULL && sc != &scs) |
| syncache_free(sc); |
| if (s != NULL) |
| bsd_free(s, M_TCPLOG); |
| *lsop = NULL; |
| return (0); |
| } |
| |
| int |
| tcp_offload_syncache_expand(struct in_conninfo *inc, struct toeopt *toeo, |
| struct tcphdr *th, struct socket **lsop, struct mbuf *m) |
| { |
| struct tcpopt to; |
| int rc; |
| |
| bzero(&to, sizeof(struct tcpopt)); |
| to.to_mss = toeo->to_mss; |
| to.to_wscale = toeo->to_wscale; |
| to.to_flags = toeo->to_flags; |
| |
| INP_INFO_WLOCK(&V_tcbinfo); |
| rc = syncache_expand(inc, &to, th, lsop, m); |
| INP_INFO_WUNLOCK(&V_tcbinfo); |
| |
| return (rc); |
| } |
| |
| /* |
| * Given a LISTEN socket and an inbound SYN request, add |
| * this to the syn cache, and send back a segment: |
| * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK> |
| * to the source. |
| * |
| * IMPORTANT NOTE: We do _NOT_ ACK data that might accompany the SYN. |
| * Doing so would require that we hold onto the data and deliver it |
| * to the application. However, if we are the target of a SYN-flood |
| * DoS attack, an attacker could send data which would eventually |
| * consume all available buffer space if it were ACKed. By not ACKing |
| * the data, we avoid this DoS scenario. |
| */ |
| static void |
| _syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th, |
| struct inpcb *inp, struct socket **lsop, struct mbuf *m, |
| struct toe_usrreqs *tu, void *toepcb) |
| { |
| struct tcpcb *tp; |
| struct socket *so; |
| struct syncache *sc = NULL; |
| struct syncache_head *sch; |
| struct mbuf *ipopts = NULL; |
| u_int32_t flowtmp; |
| int win, sb_hiwat, ip_ttl, ip_tos, noopt; |
| char *s; |
| #ifdef INET6 |
| int autoflowlabel = 0; |
| #endif |
| #ifdef MAC |
| struct label *maclabel; |
| #endif |
| struct syncache scs; |
| struct ucred *cred; |
| |
| INP_INFO_WLOCK_ASSERT(&V_tcbinfo); |
| INP_WLOCK_ASSERT(inp); /* listen socket */ |
| KASSERT((th->th_flags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN, |
| ("%s: unexpected tcp flags", __func__)); |
| |
| /* |
| * Combine all so/tp operations very early to drop the INP lock as |
| * soon as possible. |
| */ |
| so = *lsop; |
| tp = sototcpcb(so); |
| cred = NULL;//crhold(so->so_cred); |
| |
| #ifdef INET6 |
| if ((inc->inc_flags & INC_ISIPV6) && |
| (inp->inp_flags & IN6P_AUTOFLOWLABEL)) |
| autoflowlabel = 1; |
| #endif |
| ip_ttl = inp->inp_ip_ttl; |
| ip_tos = inp->inp_ip_tos; |
| win = sbspace(&so->so_rcv); |
| sb_hiwat = so->so_rcv.sb_hiwat; |
| noopt = (tp->t_flags & TF_NOOPT); |
| |
| /* By the time we drop the lock these should no longer be used. */ |
| so = NULL; |
| tp = NULL; |
| |
| #ifdef MAC |
| if (mac_syncache_init(&maclabel) != 0) { |
| INP_WUNLOCK(inp); |
| INP_INFO_WUNLOCK(&V_tcbinfo); |
| goto done; |
| } else |
| mac_syncache_create(maclabel, inp); |
| #endif |
| INP_WUNLOCK(inp); |
| INP_INFO_WUNLOCK(&V_tcbinfo); |
| |
| /* |
| * Remember the IP options, if any. |
| */ |
| #ifdef INET6 |
| if (!(inc->inc_flags & INC_ISIPV6)) |
| #endif |
| ipopts = (m) ? ip_srcroute(m) : NULL; |
| |
| /* |
| * See if we already have an entry for this connection. |
| * If we do, resend the SYN,ACK, and reset the retransmit timer. |
| * |
| * XXX: should the syncache be re-initialized with the contents |
| * of the new SYN here (which may have different options?) |
| * |
| * XXX: We do not check the sequence number to see if this is a |
| * real retransmit or a new connection attempt. The question is |
| * how to handle such a case; either ignore it as spoofed, or |
| * drop the current entry and create a new one? |
| */ |
| sc = syncache_lookup(inc, &sch); /* returns locked entry */ |
| SCH_LOCK_ASSERT(sch); |
| if (sc != NULL) { |
| #ifndef TCP_OFFLOAD_DISABLE |
| if (sc->sc_tu) |
| sc->sc_tu->tu_syncache_event(TOE_SC_ENTRY_PRESENT, |
| sc->sc_toepcb); |
| #endif |
| TCPSTAT_INC(tcps_sc_dupsyn); |
| if (ipopts) { |
| /* |
| * If we were remembering a previous source route, |
| * forget it and use the new one we've been given. |
| */ |
| if (sc->sc_ipopts) |
| (void) m_free(sc->sc_ipopts); |
| sc->sc_ipopts = ipopts; |
| } |
| /* |
| * Update timestamp if present. |
| */ |
| if ((sc->sc_flags & SCF_TIMESTAMP) && (to->to_flags & TOF_TS)) |
| sc->sc_tsreflect = to->to_tsval; |
| else |
| sc->sc_flags &= ~SCF_TIMESTAMP; |
| #ifdef MAC |
| /* |
| * Since we have already unconditionally allocated label |
| * storage, free it up. The syncache entry will already |
| * have an initialized label we can use. |
| */ |
| mac_syncache_destroy(&maclabel); |
| #endif |
| /* Retransmit SYN|ACK and reset retransmit count. */ |
| if ((s = tcp_log_addrs(&sc->sc_inc, th, NULL, NULL))) { |
| bsd_log(LOG_DEBUG, "%s; %s: Received duplicate SYN, " |
| "resetting timer and retransmitting SYN|ACK\n", |
| s, __func__); |
| bsd_free(s, M_TCPLOG); |
| } |
| if (!TOEPCB_ISSET(sc) && syncache_respond(sc) == 0) { |
| sc->sc_rxmits = 0; |
| syncache_timeout(sc, sch, 1); |
| TCPSTAT_INC(tcps_sndacks); |
| TCPSTAT_INC(tcps_sndtotal); |
| } |
| SCH_UNLOCK(sch); |
| goto done; |
| } |
| |
| sc = uma_zalloc(V_tcp_syncache.zone, M_NOWAIT | M_ZERO); |
| if (sc == NULL) { |
| /* |
| * The zone allocator couldn't provide more entries. |
| * Treat this as if the cache was full; drop the oldest |
| * entry and insert the new one. |
| */ |
| TCPSTAT_INC(tcps_sc_zonefail); |
| if ((sc = TAILQ_LAST(&sch->sch_bucket, sch_head)) != NULL) |
| syncache_drop(sc, sch); |
| sc = uma_zalloc(V_tcp_syncache.zone, M_NOWAIT | M_ZERO); |
| if (sc == NULL) { |
| if (V_tcp_syncookies) { |
| bzero(&scs, sizeof(scs)); |
| sc = &scs; |
| } else { |
| SCH_UNLOCK(sch); |
| if (ipopts) |
| (void) m_free(ipopts); |
| goto done; |
| } |
| } |
| } |
| |
| /* |
| * Fill in the syncache values. |
| */ |
| #ifdef MAC |
| sc->sc_label = maclabel; |
| #endif |
| sc->sc_cred = cred; |
| cred = NULL; |
| sc->sc_ipopts = ipopts; |
| bcopy(inc, &sc->sc_inc, sizeof(struct in_conninfo)); |
| #ifdef INET6 |
| if (!(inc->inc_flags & INC_ISIPV6)) |
| #endif |
| { |
| sc->sc_ip_tos = ip_tos; |
| sc->sc_ip_ttl = ip_ttl; |
| } |
| #ifndef TCP_OFFLOAD_DISABLE |
| sc->sc_tu = tu; |
| sc->sc_toepcb = toepcb; |
| #endif |
| sc->sc_irs = th->th_seq; |
| sc->sc_iss = arc4random(); |
| sc->sc_flags = 0; |
| sc->sc_flowlabel = 0; |
| |
| /* |
| * Initial receive window: clip sbspace to [0 .. TCP_MAXWIN]. |
| * win was derived from socket earlier in the function. |
| */ |
| win = imax(win, 0); |
| win = imin(win, TCP_MAXWIN); |
| sc->sc_wnd = win; |
| |
| if (V_tcp_do_rfc1323) { |
| /* |
| * A timestamp received in a SYN makes |
| * it ok to send timestamp requests and replies. |
| */ |
| if (to->to_flags & TOF_TS) { |
| sc->sc_tsreflect = to->to_tsval; |
| sc->sc_ts = bsd_ticks; |
| sc->sc_flags |= SCF_TIMESTAMP; |
| } |
| if (to->to_flags & TOF_SCALE) { |
| int wscale = 0; |
| |
| /* |
| * Pick the smallest possible scaling factor that |
| * will still allow us to scale up to sb_max, aka |
| * kern.ipc.maxsockbuf. |
| * |
| * We do this because there are broken firewalls that |
| * will corrupt the window scale option, leading to |
| * the other endpoint believing that our advertised |
| * window is unscaled. At scale factors larger than |
| * 5 the unscaled window will drop below 1500 bytes, |
| * leading to serious problems when traversing these |
| * broken firewalls. |
| * |
| * With the default maxsockbuf of 256K, a scale factor |
| * of 3 will be chosen by this algorithm. Those who |
| * choose a larger maxsockbuf should watch out |
| * for the compatiblity problems mentioned above. |
| * |
| * RFC1323: The Window field in a SYN (i.e., a <SYN> |
| * or <SYN,ACK>) segment itself is never scaled. |
| */ |
| while (wscale < TCP_MAX_WINSHIFT && |
| (TCP_MAXWIN << wscale) < sb_max) |
| wscale++; |
| sc->sc_requested_r_scale = wscale; |
| sc->sc_requested_s_scale = to->to_wscale; |
| sc->sc_flags |= SCF_WINSCALE; |
| } |
| } |
| #ifdef TCP_SIGNATURE |
| /* |
| * If listening socket requested TCP digests, and received SYN |
| * contains the option, flag this in the syncache so that |
| * syncache_respond() will do the right thing with the SYN+ACK. |
| * XXX: Currently we always record the option by default and will |
| * attempt to use it in syncache_respond(). |
| */ |
| if (to->to_flags & TOF_SIGNATURE) |
| sc->sc_flags |= SCF_SIGNATURE; |
| #endif |
| if (to->to_flags & TOF_SACKPERM) |
| sc->sc_flags |= SCF_SACK; |
| if (to->to_flags & TOF_MSS) |
| sc->sc_peer_mss = to->to_mss; /* peer mss may be zero */ |
| if (noopt) |
| sc->sc_flags |= SCF_NOOPT; |
| if ((th->th_flags & (TH_ECE|TH_CWR)) && V_tcp_do_ecn) |
| sc->sc_flags |= SCF_ECN; |
| |
| if (V_tcp_syncookies) { |
| syncookie_generate(sch, sc, &flowtmp); |
| #ifdef INET6 |
| if (autoflowlabel) |
| sc->sc_flowlabel = flowtmp; |
| #endif |
| } else { |
| #ifdef INET6 |
| if (autoflowlabel) |
| sc->sc_flowlabel = |
| (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK); |
| #endif |
| } |
| SCH_UNLOCK(sch); |
| |
| /* |
| * Do a standard 3-way handshake. |
| */ |
| if (TOEPCB_ISSET(sc) || syncache_respond(sc) == 0) { |
| if (V_tcp_syncookies && V_tcp_syncookiesonly && sc != &scs) |
| syncache_free(sc); |
| else if (sc != &scs) |
| syncache_insert(sc, sch); /* locks and unlocks sch */ |
| TCPSTAT_INC(tcps_sndacks); |
| TCPSTAT_INC(tcps_sndtotal); |
| } else { |
| if (sc != &scs) |
| syncache_free(sc); |
| TCPSTAT_INC(tcps_sc_dropped); |
| } |
| |
| done: |
| //if (cred != NULL) |
| // crfree(cred); |
| #ifdef MAC |
| if (sc == &scs) |
| mac_syncache_destroy(&maclabel); |
| #endif |
| if (m) { |
| |
| *lsop = NULL; |
| m_freem(m); |
| } |
| } |
| |
| static int |
| syncache_respond(struct syncache *sc) |
| { |
| struct ip *ip = NULL; |
| struct mbuf *m; |
| struct tcphdr *th; |
| int optlen, error; |
| u_int16_t hlen, tlen, mssopt; |
| struct tcpopt to; |
| #ifdef INET6 |
| struct ip6_hdr *ip6 = NULL; |
| #endif |
| |
| hlen = |
| #ifdef INET6 |
| (sc->sc_inc.inc_flags & INC_ISIPV6) ? sizeof(struct ip6_hdr) : |
| #endif |
| sizeof(struct ip); |
| tlen = hlen + sizeof(struct tcphdr); |
| |
| /* Determine MSS we advertize to other end of connection. */ |
| mssopt = tcp_mssopt(&sc->sc_inc); |
| if (sc->sc_peer_mss) |
| mssopt = max( min(sc->sc_peer_mss, mssopt), V_tcp_minmss); |
| |
| /* XXX: Assume that the entire packet will fit in a header mbuf. */ |
| KASSERT(max_linkhdr + tlen + TCP_MAXOLEN <= MHLEN, |
| ("syncache: mbuf too small")); |
| |
| /* Create the IP+TCP header from scratch. */ |
| m = m_gethdr(M_DONTWAIT, MT_DATA); |
| if (m == NULL) |
| return (ENOBUFS); |
| #ifdef MAC |
| mac_syncache_create_mbuf(sc->sc_label, m); |
| #endif |
| m->m_data += max_linkhdr; |
| m->m_len = tlen; |
| m->m_pkthdr.len = tlen; |
| m->m_pkthdr.rcvif = NULL; |
| |
| #ifdef INET6 |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) { |
| ip6 = mtod(m, struct ip6_hdr *); |
| ip6->ip6_vfc = IPV6_VERSION; |
| ip6->ip6_nxt = IPPROTO_TCP; |
| ip6->ip6_src = sc->sc_inc.inc6_laddr; |
| ip6->ip6_dst = sc->sc_inc.inc6_faddr; |
| ip6->ip6_plen = htons(tlen - hlen); |
| /* ip6_hlim is set after checksum */ |
| ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; |
| ip6->ip6_flow |= sc->sc_flowlabel; |
| |
| th = (struct tcphdr *)(ip6 + 1); |
| } else |
| #endif |
| { |
| ip = mtod(m, struct ip *); |
| ip->ip_v = IPVERSION; |
| ip->ip_hl = sizeof(struct ip) >> 2; |
| ip->ip_len = tlen; |
| ip->ip_id = 0; |
| ip->ip_off = 0; |
| ip->ip_sum = 0; |
| ip->ip_p = IPPROTO_TCP; |
| ip->ip_src = sc->sc_inc.inc_laddr; |
| ip->ip_dst = sc->sc_inc.inc_faddr; |
| ip->ip_ttl = sc->sc_ip_ttl; |
| ip->ip_tos = sc->sc_ip_tos; |
| |
| /* |
| * See if we should do MTU discovery. Route lookups are |
| * expensive, so we will only unset the DF bit if: |
| * |
| * 1) path_mtu_discovery is disabled |
| * 2) the SCF_UNREACH flag has been set |
| */ |
| if (V_path_mtu_discovery && ((sc->sc_flags & SCF_UNREACH) == 0)) |
| ip->ip_off |= IP_DF; |
| |
| th = (struct tcphdr *)(ip + 1); |
| } |
| th->th_sport = sc->sc_inc.inc_lport; |
| th->th_dport = sc->sc_inc.inc_fport; |
| |
| th->th_seq = htonl(sc->sc_iss); |
| th->th_ack = htonl(sc->sc_irs + 1); |
| th->th_off = sizeof(struct tcphdr) >> 2; |
| th->th_x2 = 0; |
| th->th_flags = TH_SYN|TH_ACK; |
| th->th_win = htons(sc->sc_wnd); |
| th->th_urp = 0; |
| |
| if (sc->sc_flags & SCF_ECN) { |
| th->th_flags |= TH_ECE; |
| TCPSTAT_INC(tcps_ecn_shs); |
| } |
| |
| /* Tack on the TCP options. */ |
| if ((sc->sc_flags & SCF_NOOPT) == 0) { |
| to.to_flags = 0; |
| |
| to.to_mss = mssopt; |
| to.to_flags = TOF_MSS; |
| if (sc->sc_flags & SCF_WINSCALE) { |
| to.to_wscale = sc->sc_requested_r_scale; |
| to.to_flags |= TOF_SCALE; |
| } |
| if (sc->sc_flags & SCF_TIMESTAMP) { |
| /* Virgin timestamp or TCP cookie enhanced one. */ |
| to.to_tsval = sc->sc_ts; |
| to.to_tsecr = sc->sc_tsreflect; |
| to.to_flags |= TOF_TS; |
| } |
| if (sc->sc_flags & SCF_SACK) |
| to.to_flags |= TOF_SACKPERM; |
| #ifdef TCP_SIGNATURE |
| if (sc->sc_flags & SCF_SIGNATURE) |
| to.to_flags |= TOF_SIGNATURE; |
| #endif |
| optlen = tcp_addoptions(&to, (u_char *)(th + 1)); |
| |
| /* Adjust headers by option size. */ |
| th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; |
| m->m_len += optlen; |
| m->m_pkthdr.len += optlen; |
| |
| #ifdef TCP_SIGNATURE |
| if (sc->sc_flags & SCF_SIGNATURE) |
| tcp_signature_compute(m, 0, 0, optlen, |
| to.to_signature, IPSEC_DIR_OUTBOUND); |
| #endif |
| #ifdef INET6 |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) |
| ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) + optlen); |
| else |
| #endif |
| ip->ip_len += optlen; |
| } else |
| optlen = 0; |
| |
| M_SETFIB(m, sc->sc_inc.inc_fibnum); |
| #ifdef INET6 |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) { |
| th->th_sum = 0; |
| th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, |
| tlen + optlen - hlen); |
| ip6->ip6_hlim = in6_selecthlim(NULL, NULL); |
| error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); |
| } else |
| #endif |
| { |
| th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, |
| htons(tlen + optlen - hlen + IPPROTO_TCP)); |
| m->m_pkthdr.csum_flags = CSUM_TCP; |
| m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); |
| error = ip_output(m, sc->sc_ipopts, NULL, 0, NULL, NULL); |
| } |
| return (error); |
| } |
| |
| void |
| syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th, |
| struct inpcb *inp, struct socket **lsop, struct mbuf *m) |
| { |
| _syncache_add(inc, to, th, inp, lsop, m, NULL, NULL); |
| } |
| |
| void |
| tcp_offload_syncache_add(struct in_conninfo *inc, struct toeopt *toeo, |
| struct tcphdr *th, struct inpcb *inp, struct socket **lsop, |
| struct toe_usrreqs *tu, void *toepcb) |
| { |
| struct tcpopt to; |
| |
| bzero(&to, sizeof(struct tcpopt)); |
| to.to_mss = toeo->to_mss; |
| to.to_wscale = toeo->to_wscale; |
| to.to_flags = toeo->to_flags; |
| |
| INP_INFO_WLOCK(&V_tcbinfo); |
| INP_WLOCK(inp); |
| |
| _syncache_add(inc, &to, th, inp, lsop, NULL, tu, toepcb); |
| } |
| |
| /* |
| * The purpose of SYN cookies is to avoid keeping track of all SYN's we |
| * receive and to be able to handle SYN floods from bogus source addresses |
| * (where we will never receive any reply). SYN floods try to exhaust all |
| * our memory and available slots in the SYN cache table to cause a denial |
| * of service to legitimate users of the local host. |
| * |
| * The idea of SYN cookies is to encode and include all necessary information |
| * about the connection setup state within the SYN-ACK we send back and thus |
| * to get along without keeping any local state until the ACK to the SYN-ACK |
| * arrives (if ever). Everything we need to know should be available from |
| * the information we encoded in the SYN-ACK. |
| * |
| * More information about the theory behind SYN cookies and its first |
| * discussion and specification can be found at: |
| * http://cr.yp.to/syncookies.html (overview) |
| * http://cr.yp.to/syncookies/archive (gory details) |
| * |
| * This implementation extends the orginal idea and first implementation |
| * of FreeBSD by using not only the initial sequence number field to store |
| * information but also the timestamp field if present. This way we can |
| * keep track of the entire state we need to know to recreate the session in |
| * its original form. Almost all TCP speakers implement RFC1323 timestamps |
| * these days. For those that do not we still have to live with the known |
| * shortcomings of the ISN only SYN cookies. |
| * |
| * Cookie layers: |
| * |
| * Initial sequence number we send: |
| * 31|................................|0 |
| * DDDDDDDDDDDDDDDDDDDDDDDDDMMMRRRP |
| * D = MD5 Digest (first dword) |
| * M = MSS index |
| * R = Rotation of secret |
| * P = Odd or Even secret |
| * |
| * The MD5 Digest is computed with over following parameters: |
| * a) randomly rotated secret |
| * b) struct in_conninfo containing the remote/local ip/port (IPv4&IPv6) |
| * c) the received initial sequence number from remote host |
| * d) the rotation offset and odd/even bit |
| * |
| * Timestamp we send: |
| * 31|................................|0 |
| * DDDDDDDDDDDDDDDDDDDDDDSSSSRRRRA5 |
| * D = MD5 Digest (third dword) (only as filler) |
| * S = Requested send window scale |
| * R = Requested receive window scale |
| * A = SACK allowed |
| * 5 = TCP-MD5 enabled (not implemented yet) |
| * XORed with MD5 Digest (forth dword) |
| * |
| * The timestamp isn't cryptographically secure and doesn't need to be. |
| * The double use of the MD5 digest dwords ties it to a specific remote/ |
| * local host/port, remote initial sequence number and our local time |
| * limited secret. A received timestamp is reverted (XORed) and then |
| * the contained MD5 dword is compared to the computed one to ensure the |
| * timestamp belongs to the SYN-ACK we sent. The other parameters may |
| * have been tampered with but this isn't different from supplying bogus |
| * values in the SYN in the first place. |
| * |
| * Some problems with SYN cookies remain however: |
| * Consider the problem of a recreated (and retransmitted) cookie. If the |
| * original SYN was accepted, the connection is established. The second |
| * SYN is inflight, and if it arrives with an ISN that falls within the |
| * receive window, the connection is killed. |
| * |
| * Notes: |
| * A heuristic to determine when to accept syn cookies is not necessary. |
| * An ACK flood would cause the syncookie verification to be attempted, |
| * but a SYN flood causes syncookies to be generated. Both are of equal |
| * cost, so there's no point in trying to optimize the ACK flood case. |
| * Also, if you don't process certain ACKs for some reason, then all someone |
| * would have to do is launch a SYN and ACK flood at the same time, which |
| * would stop cookie verification and defeat the entire purpose of syncookies. |
| */ |
| static int tcp_sc_msstab[] = { 0, 256, 468, 536, 996, 1452, 1460, 8960 }; |
| |
| static void |
| syncookie_generate(struct syncache_head *sch, struct syncache *sc, |
| u_int32_t *flowlabel) |
| { |
| MD5_CTX ctx; |
| u_int32_t md5_buffer[MD5_DIGEST_LENGTH / sizeof(u_int32_t)]; |
| u_int32_t data; |
| u_int32_t *secbits; |
| u_int off, pmss, mss; |
| int i; |
| |
| SCH_LOCK_ASSERT(sch); |
| |
| /* Which of the two secrets to use. */ |
| secbits = sch->sch_oddeven ? |
| sch->sch_secbits_odd : sch->sch_secbits_even; |
| |
| /* Reseed secret if too old. */ |
| if (sch->sch_reseed < time_uptime) { |
| sch->sch_oddeven = sch->sch_oddeven ? 0 : 1; /* toggle */ |
| secbits = sch->sch_oddeven ? |
| sch->sch_secbits_odd : sch->sch_secbits_even; |
| for (i = 0; i < SYNCOOKIE_SECRET_SIZE; i++) |
| secbits[i] = arc4random(); |
| sch->sch_reseed = time_uptime + SYNCOOKIE_LIFETIME; |
| } |
| |
| /* Secret rotation offset. */ |
| off = sc->sc_iss & 0x7; /* iss was randomized before */ |
| |
| /* Maximum segment size calculation. */ |
| pmss = |
| max( min(sc->sc_peer_mss, tcp_mssopt(&sc->sc_inc)), V_tcp_minmss); |
| for (mss = sizeof(tcp_sc_msstab) / sizeof(int) - 1; mss > 0; mss--) |
| if (tcp_sc_msstab[mss] <= pmss) |
| break; |
| |
| /* Fold parameters and MD5 digest into the ISN we will send. */ |
| data = sch->sch_oddeven;/* odd or even secret, 1 bit */ |
| data |= off << 1; /* secret offset, derived from iss, 3 bits */ |
| data |= mss << 4; /* mss, 3 bits */ |
| |
| MD5Init(&ctx); |
| MD5Update(&ctx, ((u_int8_t *)secbits) + off, |
| SYNCOOKIE_SECRET_SIZE * sizeof(*secbits) - off); |
| MD5Update(&ctx, secbits, off); |
| MD5Update(&ctx, &sc->sc_inc, sizeof(sc->sc_inc)); |
| MD5Update(&ctx, &sc->sc_irs, sizeof(sc->sc_irs)); |
| MD5Update(&ctx, &data, sizeof(data)); |
| MD5Final((u_int8_t *)&md5_buffer, &ctx); |
| |
| data |= (md5_buffer[0] << 7); |
| sc->sc_iss = data; |
| |
| #ifdef INET6 |
| *flowlabel = md5_buffer[1] & IPV6_FLOWLABEL_MASK; |
| #endif |
| |
| /* Additional parameters are stored in the timestamp if present. */ |
| if (sc->sc_flags & SCF_TIMESTAMP) { |
| data = ((sc->sc_flags & SCF_SIGNATURE) ? 1 : 0); /* TCP-MD5, 1 bit */ |
| data |= ((sc->sc_flags & SCF_SACK) ? 1 : 0) << 1; /* SACK, 1 bit */ |
| data |= sc->sc_requested_s_scale << 2; /* SWIN scale, 4 bits */ |
| data |= sc->sc_requested_r_scale << 6; /* RWIN scale, 4 bits */ |
| data |= md5_buffer[2] << 10; /* more digest bits */ |
| data ^= md5_buffer[3]; |
| sc->sc_ts = data; |
| sc->sc_tsoff = data - bsd_ticks; /* after XOR */ |
| } |
| |
| TCPSTAT_INC(tcps_sc_sendcookie); |
| } |
| |
| static struct syncache * |
| syncookie_lookup(struct in_conninfo *inc, struct syncache_head *sch, |
| struct syncache *sc, struct tcpopt *to, struct tcphdr *th, |
| struct socket *so) |
| { |
| MD5_CTX ctx; |
| u_int32_t md5_buffer[MD5_DIGEST_LENGTH / sizeof(u_int32_t)]; |
| u_int32_t data = 0; |
| u_int32_t *secbits; |
| tcp_seq ack, seq; |
| int off, mss, wnd, flags; |
| |
| SCH_LOCK_ASSERT(sch); |
| |
| /* |
| * Pull information out of SYN-ACK/ACK and |
| * revert sequence number advances. |
| */ |
| ack = th->th_ack - 1; |
| seq = th->th_seq - 1; |
| off = (ack >> 1) & 0x7; |
| mss = (ack >> 4) & 0x7; |
| flags = ack & 0x7f; |
| |
| /* Which of the two secrets to use. */ |
| secbits = (flags & 0x1) ? sch->sch_secbits_odd : sch->sch_secbits_even; |
| |
| /* |
| * The secret wasn't updated for the lifetime of a syncookie, |
| * so this SYN-ACK/ACK is either too old (replay) or totally bogus. |
| */ |
| if (sch->sch_reseed + SYNCOOKIE_LIFETIME < time_uptime) { |
| return (NULL); |
| } |
| |
| /* Recompute the digest so we can compare it. */ |
| MD5Init(&ctx); |
| MD5Update(&ctx, ((u_int8_t *)secbits) + off, |
| SYNCOOKIE_SECRET_SIZE * sizeof(*secbits) - off); |
| MD5Update(&ctx, secbits, off); |
| MD5Update(&ctx, inc, sizeof(*inc)); |
| MD5Update(&ctx, &seq, sizeof(seq)); |
| MD5Update(&ctx, &flags, sizeof(flags)); |
| MD5Final((u_int8_t *)&md5_buffer, &ctx); |
| |
| /* Does the digest part of or ACK'ed ISS match? */ |
| if ((ack & (~0x7f)) != (md5_buffer[0] << 7)) |
| return (NULL); |
| |
| /* Does the digest part of our reflected timestamp match? */ |
| if (to->to_flags & TOF_TS) { |
| data = md5_buffer[3] ^ to->to_tsecr; |
| if ((data & (~0x3ff)) != (md5_buffer[2] << 10)) |
| return (NULL); |
| } |
| |
| /* Fill in the syncache values. */ |
| bcopy(inc, &sc->sc_inc, sizeof(struct in_conninfo)); |
| sc->sc_ipopts = NULL; |
| |
| sc->sc_irs = seq; |
| sc->sc_iss = ack; |
| |
| #ifdef INET6 |
| if (inc->inc_flags & INC_ISIPV6) { |
| if (sotoinpcb(so)->inp_flags & IN6P_AUTOFLOWLABEL) |
| sc->sc_flowlabel = md5_buffer[1] & IPV6_FLOWLABEL_MASK; |
| } else |
| #endif |
| { |
| sc->sc_ip_ttl = sotoinpcb(so)->inp_ip_ttl; |
| sc->sc_ip_tos = sotoinpcb(so)->inp_ip_tos; |
| } |
| |
| /* Additional parameters that were encoded in the timestamp. */ |
| if (data) { |
| sc->sc_flags |= SCF_TIMESTAMP; |
| sc->sc_tsreflect = to->to_tsval; |
| sc->sc_ts = to->to_tsecr; |
| sc->sc_tsoff = to->to_tsecr - bsd_ticks; |
| sc->sc_flags |= (data & 0x1) ? SCF_SIGNATURE : 0; |
| sc->sc_flags |= ((data >> 1) & 0x1) ? SCF_SACK : 0; |
| sc->sc_requested_s_scale = min((data >> 2) & 0xf, |
| TCP_MAX_WINSHIFT); |
| sc->sc_requested_r_scale = min((data >> 6) & 0xf, |
| TCP_MAX_WINSHIFT); |
| if (sc->sc_requested_s_scale || sc->sc_requested_r_scale) |
| sc->sc_flags |= SCF_WINSCALE; |
| } else |
| sc->sc_flags |= SCF_NOOPT; |
| |
| wnd = sbspace(&so->so_rcv); |
| wnd = imax(wnd, 0); |
| wnd = imin(wnd, TCP_MAXWIN); |
| sc->sc_wnd = wnd; |
| |
| sc->sc_rxmits = 0; |
| sc->sc_peer_mss = tcp_sc_msstab[mss]; |
| |
| TCPSTAT_INC(tcps_sc_recvcookie); |
| return (sc); |
| } |
| |
| /* |
| * Returns the current number of syncache entries. This number |
| * will probably change before you get around to calling |
| * syncache_pcblist. |
| */ |
| |
| int |
| syncache_pcbcount(void) |
| { |
| struct syncache_head *sch; |
| int count, i; |
| |
| for (count = 0, i = 0; i < V_tcp_syncache.hashsize; i++) { |
| /* No need to lock for a read. */ |
| sch = &V_tcp_syncache.hashbase[i]; |
| count += sch->sch_length; |
| } |
| return count; |
| } |
| |
| /* |
| * Exports the syncache entries to userland so that netstat can display |
| * them alongside the other sockets. This function is intended to be |
| * called only from tcp_pcblist. |
| * |
| * Due to concurrency on an active system, the number of pcbs exported |
| * may have no relation to max_pcbs. max_pcbs merely indicates the |
| * amount of space the caller allocated for this function to use. |
| */ |
| /* |
| int |
| syncache_pcblist(struct sysctl_req *req, int max_pcbs, int *pcbs_exported) |
| { |
| struct xtcpcb xt; |
| struct syncache *sc; |
| struct syncache_head *sch; |
| int count, error, i; |
| |
| for (count = 0, error = 0, i = 0; i < V_tcp_syncache.hashsize; i++) { |
| sch = &V_tcp_syncache.hashbase[i]; |
| SCH_LOCK(sch); |
| TAILQ_FOREACH(sc, &sch->sch_bucket, sc_hash) { |
| if (count >= max_pcbs) { |
| SCH_UNLOCK(sch); |
| goto exit; |
| } |
| if (cr_cansee(req->td->td_ucred, sc->sc_cred) != 0) |
| continue; |
| bzero(&xt, sizeof(xt)); |
| xt.xt_len = sizeof(xt); |
| if (sc->sc_inc.inc_flags & INC_ISIPV6) |
| xt.xt_inp.inp_vflag = INP_IPV6; |
| else |
| xt.xt_inp.inp_vflag = INP_IPV4; |
| bcopy(&sc->sc_inc, &xt.xt_inp.inp_inc, sizeof (struct in_conninfo)); |
| xt.xt_tp.t_inpcb = &xt.xt_inp; |
| xt.xt_tp.t_state = TCPS_SYN_RECEIVED; |
| xt.xt_socket.xso_protocol = IPPROTO_TCP; |
| xt.xt_socket.xso_len = sizeof (struct xsocket); |
| xt.xt_socket.so_type = SOCK_STREAM; |
| xt.xt_socket.so_state = SS_ISCONNECTING; |
| error = SYSCTL_OUT(req, &xt, sizeof xt); |
| if (error) { |
| SCH_UNLOCK(sch); |
| goto exit; |
| } |
| count++; |
| } |
| SCH_UNLOCK(sch); |
| } |
| exit: |
| *pcbs_exported = count; |
| return error; |
| }*/ |