X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=site.c;h=c452011e5538a6c7458928d9a0e3853ade0be1f5;hp=e6c34c8dffdaccc5edb042304fa91115e9cc1d6a;hb=2694a33edb14ea5abf5637e4a88a5aeff2e77453;hpb=e001e8c056deecfdd295638262a9d61ca9995e23

diff --git a/site.c b/site.c
index e6c34c8..c452011 100644
--- a/site.c
+++ b/site.c
@@ -229,11 +229,12 @@ struct site {
 /* configuration information */
     string_t localname;
     string_t remotename;
-    bool_t peer_mobile; /* Mobile client support */
+    bool_t local_mobile, peer_mobile; /* Mobile client support */
     int32_t transport_peers_max;
     string_t tunname; /* localname<->remotename by default, used in logs */
     string_t address; /* DNS name for bootstrapping, optional */
     int remoteport; /* Port for bootstrapping, optional */
+    uint32_t mtu_target;
     struct netlink_if *netlink;
     struct comm_if **comms;
     int ncomms;
@@ -266,6 +267,7 @@ struct site {
     uint32_t state;
     uint64_t now; /* Most recently seen time */
     bool_t allow_send_prod;
+    bool_t resolving;
 
     /* The currently established session */
     struct data_key current;
@@ -282,6 +284,7 @@ struct site {
        timeout before we can listen for another setup packet); perhaps
        we should keep a list of 'bad' sources for setup packets. */
     uint32_t remote_capabilities;
+    uint16_t remote_adv_mtu;
     struct transform_if *chosen_transform;
     uint32_t setup_session_id;
     transport_peers setup_peers;
@@ -297,35 +300,75 @@ struct site {
     struct transform_inst_if *new_transform; /* For key setup/verify */
 };
 
+static uint32_t event_log_priority(struct site *st, uint32_t event)
+{
+    if (!(event&st->log_events))
+	return 0;
+    switch(event) {
+    case LOG_UNEXPECTED:    return M_INFO;
+    case LOG_SETUP_INIT:    return M_INFO;
+    case LOG_SETUP_TIMEOUT: return M_NOTICE;
+    case LOG_ACTIVATE_KEY:  return M_INFO;
+    case LOG_TIMEOUT_KEY:   return M_INFO;
+    case LOG_SEC:           return M_SECURITY;
+    case LOG_STATE:         return M_DEBUG;
+    case LOG_DROP:          return M_DEBUG;
+    case LOG_DUMP:          return M_DEBUG;
+    case LOG_ERROR:         return M_ERR;
+    case LOG_PEER_ADDRS:    return M_DEBUG;
+    default:                return M_ERR;
+    }
+}
+
+static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap)
+FORMAT(printf,3,0);
+static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap)
+{
+    uint32_t class;
+
+    class=event_log_priority(st, event);
+    if (class) {
+	slilog_part(st->log,class,"%s: ",st->tunname);
+	vslilog_part(st->log,class,msg,ap);
+	slilog_part(st->log,class,"\n");
+    }
+}
+
 static void slog(struct site *st, uint32_t event, cstring_t msg, ...)
 FORMAT(printf,3,4);
 static void slog(struct site *st, uint32_t event, cstring_t msg, ...)
 {
     va_list ap;
-    char buf[240];
-    uint32_t class;
-
     va_start(ap,msg);
+    vslog(st,event,msg,ap);
+    va_end(ap);
+}
 
-    if (event&st->log_events) {
-	switch(event) {
-	case LOG_UNEXPECTED: class=M_INFO; break;
-	case LOG_SETUP_INIT: class=M_INFO; break;
-	case LOG_SETUP_TIMEOUT: class=M_NOTICE; break;
-	case LOG_ACTIVATE_KEY: class=M_INFO; break;
-	case LOG_TIMEOUT_KEY: class=M_INFO; break;
-	case LOG_SEC: class=M_SECURITY; break;
-	case LOG_STATE: class=M_DEBUG; break;
-	case LOG_DROP: class=M_DEBUG; break;
-	case LOG_DUMP: class=M_DEBUG; break;
-	case LOG_ERROR: class=M_ERR; break;
-	case LOG_PEER_ADDRS: class=M_DEBUG; break;
-	default: class=M_ERR; break;
-	}
+static void logtimeout(struct site *st, const char *fmt, ...)
+FORMAT(printf,2,3);
+static void logtimeout(struct site *st, const char *fmt, ...)
+{
+    uint32_t class=event_log_priority(st,LOG_SETUP_TIMEOUT);
+    if (!class)
+	return;
 
-	vsnprintf(buf,sizeof(buf),msg,ap);
-	slilog(st->log,class,"%s: %s",st->tunname,buf);
+    va_list ap;
+    va_start(ap,fmt);
+
+    slilog_part(st->log,class,"%s: ",st->tunname);
+    vslilog_part(st->log,class,fmt,ap);
+
+    const char *delim;
+    int i;
+    for (i=0, delim=" (tried ";
+	 i<st->setup_peers.npeers;
+	 i++, delim=", ") {
+	transport_peer *peer=&st->setup_peers.peers[i];
+	const char *s=comm_addr_to_string(&peer->addr);
+	slilog_part(st->log,class,"%s%s",delim,s);
     }
+
+    slilog_part(st->log,class,")\n");
     va_end(ap);
 }
 
@@ -386,6 +429,14 @@ static void dispose_transform(struct transform_inst_if **transform_var)
     type=buf_unprepend_uint32((b)); \
     if (type!=(t)) return False; } while(0)
 
+static _Bool type_is_msg34(uint32_t type)
+{
+    return
+	type == LABEL_MSG3 ||
+	type == LABEL_MSG3BIS ||
+	type == LABEL_MSG4;
+}
+
 struct parsedname {
     int32_t len;
     uint8_t *name;
@@ -399,6 +450,7 @@ struct msg {
     struct parsedname remote;
     struct parsedname local;
     uint32_t remote_capabilities;
+    uint16_t remote_mtu;
     int capab_transformnum;
     uint8_t *nR;
     uint8_t *nL;
@@ -487,6 +539,9 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what)
     if ((st->local_capabilities & CAPAB_EARLY) || (type != LABEL_MSG1)) {
 	buf_append_uint32(&st->buffer,st->local_capabilities);
     }
+    if (type_is_msg34(type)) {
+	buf_append_uint16(&st->buffer,st->mtu_target);
+    }
     append_string_xinfo_done(&st->buffer,&xia);
 
     buf_append_string(&st->buffer,st->remotename);
@@ -542,10 +597,15 @@ static bool_t unpick_msg(struct site *st, uint32_t type,
     CHECK_TYPE(msg,type);
     if (!unpick_name(msg,&m->remote)) return False;
     m->remote_capabilities=0;
+    m->remote_mtu=0;
     if (m->remote.extrainfo.size) {
 	CHECK_AVAIL(&m->remote.extrainfo,4);
 	m->remote_capabilities=buf_unprepend_uint32(&m->remote.extrainfo);
     }
+    if (type_is_msg34(type) && m->remote.extrainfo.size) {
+	CHECK_AVAIL(&m->remote.extrainfo,2);
+	m->remote_mtu=buf_unprepend_uint16(&m->remote.extrainfo);
+    }
     if (!unpick_name(msg,&m->local)) return False;
     if (type==LABEL_PROD) {
 	CHECK_EMPTY(msg);
@@ -639,7 +699,6 @@ static bool_t process_msg1(struct site *st, struct buffer_if *msg1,
        process an incoming MSG1, and that the MSG1 has correct values
        of A and B. */
 
-    transport_record_peer(st,&st->setup_peers,src,"msg1");
     st->setup_session_id=m->source;
     st->remote_capabilities=m->remote_capabilities;
     memcpy(st->remoteN,m->nR,NONCELEN);
@@ -722,6 +781,8 @@ static bool_t process_msg3_msg4(struct site *st, struct msg *m)
     }
     free(hash);
 
+    st->remote_adv_mtu=m->remote_mtu;
+
     return True;
 }
 
@@ -1056,7 +1117,7 @@ static bool_t send_msg(struct site *st)
 	st->retries--;
 	return True;
     } else if (st->state==SITE_SENTMSG5) {
-	slog(st,LOG_SETUP_TIMEOUT,"timed out sending MSG5, stashing new key");
+	logtimeout(st,"timed out sending MSG5, stashing new key");
 	/* We stash the key we have produced, in case it turns out that
 	 * our peer did see our MSG5 after all and starts using it. */
 	/* This is a bit like some of activate_new_key */
@@ -1074,7 +1135,7 @@ static bool_t send_msg(struct site *st)
 	enter_state_wait(st);
 	return False;
     } else {
-	slog(st,LOG_SETUP_TIMEOUT,"timed out sending key setup packet "
+	logtimeout(st,"timed out sending key setup packet "
 	    "(in state %s)",state_name(st->state));
 	enter_state_wait(st);
 	return False;
@@ -1086,10 +1147,8 @@ static void site_resolve_callback(void *sst, struct in_addr *address)
     struct site *st=sst;
     struct comm_addr ca_buf, *ca_use;
 
-    if (st->state!=SITE_RESOLVE) {
-	slog(st,LOG_UNEXPECTED,"site_resolve_callback called unexpectedly");
-	return;
-    }
+    st->resolving=False;
+
     if (address) {
 	FILLZERO(ca_buf);
 	ca_buf.comm=st->comms[0];
@@ -1097,22 +1156,73 @@ static void site_resolve_callback(void *sst, struct in_addr *address)
 	ca_buf.sin.sin_port=htons(st->remoteport);
 	ca_buf.sin.sin_addr=*address;
 	ca_use=&ca_buf;
+	slog(st,LOG_STATE,"resolution of %s completed: %s",
+	     st->address, comm_addr_to_string(ca_use));;
     } else {
 	slog(st,LOG_ERROR,"resolution of %s failed",st->address);
 	ca_use=0;
     }
-    if (transport_compute_setupinit_peers(st,ca_use,0)) {
-	enter_new_state(st,SITE_SENTMSG1);
-    } else {
-	/* Can't figure out who to try to to talk to */
-	slog(st,LOG_SETUP_INIT,"key exchange failed: cannot find peer address");
-	enter_state_run(st);
+
+    switch (st->state) {
+    case SITE_RESOLVE:
+        if (transport_compute_setupinit_peers(st,ca_use,0)) {
+	    enter_new_state(st,SITE_SENTMSG1);
+	} else {
+	    /* Can't figure out who to try to to talk to */
+	    slog(st,LOG_SETUP_INIT,
+		 "key exchange failed: cannot find peer address");
+	    enter_state_run(st);
+	}
+	break;
+    case SITE_SENTMSG1: case SITE_SENTMSG2:
+    case SITE_SENTMSG3: case SITE_SENTMSG4:
+    case SITE_SENTMSG5:
+	if (ca_use) {
+	    /* We start using the address immediately for data too.
+	     * It's best to store it in st->peers now because we might
+	     * go via SENTMSG5, WAIT, and a MSG0, straight into using
+	     * the new key (without updating the data peer addrs). */
+	    transport_record_peer(st,&st->peers,ca_use,"resolved data");
+	    transport_record_peer(st,&st->setup_peers,ca_use,"resolved setup");
+	} else if (st->local_mobile) {
+	    /* We can't let this rest because we may have a peer
+	     * address which will break in the future. */
+	    slog(st,LOG_SETUP_INIT,"resolution of %s failed: "
+		 "abandoning key exchange",st->address);
+	    enter_state_wait(st);
+	} else {
+	    slog(st,LOG_SETUP_INIT,"resolution of %s failed: "
+		 " continuing to use source address of peer's packets"
+		 " for key exchange and ultimately data",
+		 st->address);
+	}
+	break;
+    case SITE_RUN:
+	if (ca_use) {
+	    slog(st,LOG_SETUP_INIT,"resolution of %s completed tardily,"
+		 " updating peer address(es)",st->address);
+	    transport_record_peer(st,&st->peers,ca_use,"resolved tardily");
+	} else if (st->local_mobile) {
+	    /* Not very good.  We should queue (another) renegotiation
+	     * so that we can update the peer address. */
+	    st->key_renegotiate_time=st->now+st->wait_timeout;
+	} else {
+	    slog(st,LOG_SETUP_INIT,"resolution of %s failed: "
+		 " continuing to use source address of peer's packets",
+		 st->address);
+	}
+	break;
+    case SITE_WAIT:
+    case SITE_STOP:
+	/* oh well */
+	break;
     }
 }
 
 static bool_t initiate_key_setup(struct site *st, cstring_t reason,
 				 const struct comm_addr *prod_hint)
 {
+    /* Reentrancy hazard: can call enter_new_state/enter_state_* */
     if (st->state!=SITE_RUN) return False;
     slog(st,LOG_SETUP_INIT,"initiating key exchange (%s)",reason);
     if (st->address) {
@@ -1145,7 +1255,15 @@ static void activate_new_key(struct site *st)
     transport_peers_copy(st,&st->peers,&st->setup_peers);
     st->current.remote_session_id=st->setup_session_id;
 
-    slog(st,LOG_ACTIVATE_KEY,"new key activated");
+    /* Compute the inter-site MTU.  This is min( our_mtu, their_mtu ).
+     * But their mtu be unspecified, in which case we just use ours. */
+    uint32_t intersite_mtu=
+	MIN(st->mtu_target, st->remote_adv_mtu ?: ~(uint32_t)0);
+    st->netlink->set_mtu(st->netlink->st,intersite_mtu);
+
+    slog(st,LOG_ACTIVATE_KEY,"new key activated"
+	 " (mtu ours=%"PRId32" theirs=%"PRId32" intersite=%"PRId32")",
+	 st->mtu_target, st->remote_adv_mtu, intersite_mtu);
     enter_state_run(st);
 }
 
@@ -1215,14 +1333,35 @@ static void enter_state_run(struct site *st)
     set_link_quality(st);
 }
 
+static bool_t ensure_resolving(struct site *st)
+{
+    /* Reentrancy hazard: may call site_resolve_callback and hence
+     * enter_new_state, enter_state_* and generate_msg*. */
+    if (st->resolving)
+        return True;
+
+    assert(st->address);
+
+    /* resolver->request might reentrantly call site_resolve_callback
+     * which will clear st->resolving, so we need to set it beforehand
+     * rather than afterwards; also, it might return False, in which
+     * case we have to clear ->resolving again. */
+    st->resolving=True;
+    bool_t ok = st->resolver->request(st->resolver->st,st->address,
+				      site_resolve_callback,st);
+    if (!ok)
+	st->resolving=False;
+
+    return ok;
+}
+
 static bool_t enter_state_resolve(struct site *st)
 {
+    /* Reentrancy hazard!  See ensure_resolving. */
     state_assert(st,st->state==SITE_RUN);
     slog(st,LOG_STATE,"entering state RESOLVE");
     st->state=SITE_RESOLVE;
-    st->resolver->request(st->resolver->st,st->address,
-			  site_resolve_callback,st);
-    return True;
+    return ensure_resolving(st);
 }
 
 static bool_t enter_new_state(struct site *st, uint32_t next)
@@ -1488,9 +1627,14 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	if (st->state==SITE_RUN || st->state==SITE_RESOLVE ||
 	    st->state==SITE_WAIT) {
 	    /* We should definitely process it */
+	    transport_record_peer(st,&st->setup_peers,source,"msg1");
 	    if (process_msg1(st,buf,source,&named_msg)) {
 		slog(st,LOG_SETUP_INIT,"key setup initiated by peer");
-		enter_new_state(st,SITE_SENTMSG2);
+		bool_t entered=enter_new_state(st,SITE_SENTMSG2);
+		if (entered && st->address && st->local_mobile)
+		    /* We must do this as the very last thing, because
+		       the resolver callback might reenter us. */
+		    ensure_resolving(st);
 	    } else {
 		slog(st,LOG_ERROR,"failed to process incoming msg1");
 	    }
@@ -1510,6 +1654,7 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 		     "priority => use incoming msg1");
 		if (process_msg1(st,buf,source,&named_msg)) {
 		    BUF_FREE(&st->buffer); /* Free our old message 1 */
+		    transport_setup_msgok(st,source);
 		    enter_new_state(st,SITE_SENTMSG2);
 		} else {
 		    slog(st,LOG_ERROR,"failed to process an incoming "
@@ -1693,7 +1838,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     st->remotename=dict_read_string(dict, "name", True, "site", loc);
 
     st->peer_mobile=dict_read_bool(dict,"mobile",False,"site",loc,False);
-    bool_t local_mobile=
+    st->local_mobile=
 	dict_read_bool(dict,"local-mobile",False,"site",loc,False);
 
     /* Sanity check (which also allows the 'sites' file to include
@@ -1702,14 +1847,14 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     if (strcmp(st->localname,st->remotename)==0) {
 	Message(M_DEBUG,"site %s: local-name==name -> ignoring this site\n",
 		st->localname);
-	if (st->peer_mobile != local_mobile)
+	if (st->peer_mobile != st->local_mobile)
 	    cfgfatal(loc,"site","site %s's peer-mobile=%d"
 		    " but our local-mobile=%d\n",
-		    st->localname, st->peer_mobile, local_mobile);
+		    st->localname, st->peer_mobile, st->local_mobile);
 	free(st);
 	return NULL;
     }
-    if (st->peer_mobile && local_mobile) {
+    if (st->peer_mobile && st->local_mobile) {
 	Message(M_WARNING,"site %s: site is mobile but so are we"
 		" -> ignoring this site\n", st->remotename);
 	free(st);
@@ -1757,7 +1902,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     st->dh=find_cl_if(dict,"dh",CL_DH,True,"site",loc);
     st->hash=find_cl_if(dict,"hash",CL_HASH,True,"site",loc);
 
-#define DEFAULT(D) (st->peer_mobile || local_mobile	\
+#define DEFAULT(D) (st->peer_mobile || st->local_mobile	\
                     ? DEFAULT_MOBILE_##D : DEFAULT_##D)
 #define CFG_NUMBER(k,D) dict_read_number(dict,(k),False,"site",loc,DEFAULT(D));
 
@@ -1765,6 +1910,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     st->setup_retries=        CFG_NUMBER("setup-retries", SETUP_RETRIES);
     st->setup_retry_interval= CFG_NUMBER("setup-timeout", SETUP_RETRY_INTERVAL);
     st->wait_timeout=         CFG_NUMBER("wait-time",     WAIT_TIME);
+    st->mtu_target= dict_read_number(dict,"mtu-target",False,"site",loc,0);
 
     st->mobile_peer_expiry= dict_read_number(
        dict,"mobile-peer-expiry",False,"site",loc,DEFAULT_MOBILE_PEER_EXPIRY);
@@ -1791,6 +1937,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     st->log_events=string_list_to_word(dict_lookup(dict,"log-events"),
 				       log_event_table,"site");
 
+    st->resolving=False;
     st->allow_send_prod=0;
 
     st->tunname=safe_malloc(strlen(st->localname)+strlen(st->remotename)+5,
@@ -1833,7 +1980,10 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     }
 
     /* We need to register the remote networks with the netlink device */
-    st->netlink->reg(st->netlink->st, site_outgoing, st, 0);
+    uint32_t netlink_mtu; /* local virtual interface mtu */
+    st->netlink->reg(st->netlink->st, site_outgoing, st, &netlink_mtu);
+    if (!st->mtu_target)
+	st->mtu_target=netlink_mtu;
     
     for (i=0; i<st->ncomms; i++)
 	st->comms[i]->request_notify(st->comms[i]->st, st, site_incoming);
@@ -1878,14 +2028,14 @@ static void transport_peers_debug(struct site *st, transport_peers *dst,
 	 i++, (argp+=stride?stride:sizeof(*args))) {
 	const struct comm_addr *ca=(void*)argp;
 	slog(st, LOG_PEER_ADDRS, " args: addrs[%d]=%s",
-	     i, ca->comm->addr_to_string(ca->comm->st,ca));
+	     i, comm_addr_to_string(ca));
     }
     for (i=0; i<dst->npeers; i++) {
 	struct timeval diff;
 	timersub(tv_now,&dst->peers[i].last,&diff);
 	const struct comm_addr *ca=&dst->peers[i].addr;
 	slog(st, LOG_PEER_ADDRS, " peers: addrs[%d]=%s T-%ld.%06ld",
-	     i, ca->comm->addr_to_string(ca->comm->st,ca),
+	     i, comm_addr_to_string(ca),
 	     (unsigned long)diff.tv_sec, (unsigned long)diff.tv_usec);
     }
 }
@@ -1922,7 +2072,7 @@ static void transport_record_peer(struct site *st, transport_peers *peers,
 
     changed=1;
     if (peers->npeers==st->transport_peers_max)
-	slot=st->transport_peers_max;
+	slot=st->transport_peers_max-1;
     else
 	slot=peers->npeers++;
 
@@ -1953,7 +2103,7 @@ static bool_t transport_compute_setupinit_peers(struct site *st,
 	 prod_hint_addr ? " PROD hint address;" : "",
 	 st->peers.npeers);
 
-    /* Non-mobile peers havve st->peers.npeers==0 or ==1, since they
+    /* Non-mobile peers have st->peers.npeers==0 or ==1, since they
      * have transport_peers_max==1.  The effect is that this code
      * always uses the configured address if supplied, or otherwise
      * the address of the incoming PROD, or the existing data peer if