X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=site.c;h=d360699214bdd5b54bffa8738193ce06099b9a5d;hp=b04f3b340b91f9e90057636c9f6ba1b347d4f850;hb=0e646750a699f6dac806c7752c81d160c4f78987;hpb=0391d9ee80a1847381ad205b8f707e43707b90b0 diff --git a/site.c b/site.c index b04f3b3..d360699 100644 --- a/site.c +++ b/site.c @@ -40,7 +40,6 @@ #define DEFAULT_MOBILE_WAIT_TIME (10*1000) /* [ms] */ #define DEFAULT_MOBILE_PEER_EXPIRY (2*60) /* [s] */ -#define DEFAULT_MOBILE_PEERS_MAX 3 /* send at most this many copies (default) */ /* Each site can be in one of several possible states. */ @@ -143,48 +142,79 @@ static struct flagstr log_event_table[]={ /***** TRANSPORT PEERS declarations *****/ /* Details of "mobile peer" semantics: + + - We use the same data structure for the different configurations, + but manage it with different algorithms. - - We record mobile_peers_max peer address/port numbers ("peers") - for key setup, and separately mobile_peers_max for data - transfer. If these lists fill up, we retain the newest peers. - (For non-mobile peers we only record one of each.) + - We record up to mobile_peers_max peer address/port numbers + ("peers") for key setup, and separately up to mobile_peers_max + for data transfer. + + - In general, we make a new set of addrs (see below) when we start + a new key exchange; the key setup addrs become the data transport + addrs when key setup complets. + + If our peer is mobile: + + - We send to all recent addresses of incoming packets, plus + initially all configured addresses (which we also expire). - - Outgoing packets are sent to every recorded peer in the - applicable list. + - So, we record addrs of good incoming packets, as follows: + 1. expire any peers last seen >120s ("mobile-peer-expiry") ago + 2. add the peer of the just received packet to the applicable list + (possibly evicting the oldest entries to make room) + NB that we do not expire peers until an incoming packet arrives. - - Data transfer peers are straightforward: whenever we successfully - process a data packet, we record the peer. Also, whenever we - successfully complete a key setup, we merge the key setup + - If the peer has a configured address or name, we record them the + same way, but only as a result of our own initiation of key + setup. (We might evict some incoming packet addrs to make room.) + + - The default number of addrs to keep is 3, or 4 if we have a + configured name or address. That's space for two configured + addresses (one IPv6 and one IPv4), plus two received addresses. + + - Outgoing packets are sent to every recorded address in the + applicable list. Any unsupported[1] addresses are deleted from + the list right away. (This should only happen to configured + addresses, of course, but there is no need to check that.) + + - When we successfully complete a key setup, we merge the key setup peers into the data transfer peers. - (For "non-mobile" peers we simply copy the peer used for - successful key setup, and don't change the peer otherwise.) + [1] An unsupported address is one for whose AF we don't have a + socket (perhaps because we got EAFNOSUPPORT or some such) or for + which sendto gives ENETUNREACH. - - Key setup peers are slightly more complicated. + If neither end is mobile: - Whenever we receive and successfully process a key exchange - packet, we record the peer. + - When peer initiated the key exchange, we use the incoming packet + address. - Whenever we try to initiate a key setup, we copy the list of data - transfer peers and use it for key setup. But we also look to see - if the config supplies an address and port number and if so we - add that as a key setup peer (possibly evicting one of the data - transfer peers we just copied). + - When we initiate the key exchange, we try configured addresses + until we get one which isn't unsupported then fixate on that. - (For "non-mobile" peers, if we if we have a configured peer - address and port, we always use that; otherwise if we have a - current data peer address we use that; otherwise we do not - attempt to initiate a key setup for lack of a peer address.) + - When we complete a key setup, we replace the data transport peers + with those from the key setup. - "Record the peer" means - 1. expire any peers last seen >120s ("mobile-peer-expiry") ago - 2. add the peer of the just received packet to the applicable list - (possibly evicting older entries) - NB that we do not expire peers until an incoming packet arrives. + If we are mobile: - */ + - We can't tell when local network setup changes so we can't cache + the unsupported addrs and completely remove the spurious calls to + sendto, but we can optimise things a bit by deprioritising addrs + which seem to be unsupported. -#define MAX_MOBILE_PEERS_MAX 5 /* send at most this many copies, compiled max */ + - Use only configured addresses. (Except, that if our peer + initiated a key exchange we use the incoming packet address until + our name resolution completes.) + + - When we send a packet, try each address in turn; if addr + supported, put that address to the end of the list for future + packets, and go onto the next address. + + - When we complete a key setup, we replace the data transport peers + with those from the key setup. + + */ typedef struct { struct timeval last; @@ -195,21 +225,39 @@ typedef struct { /* configuration information */ /* runtime information */ int npeers; - transport_peer peers[MAX_MOBILE_PEERS_MAX]; + transport_peer peers[MAX_PEER_ADDRS]; } transport_peers; +/* Basic operations on transport peer address sets */ static void transport_peers_clear(struct site *st, transport_peers *peers); static int transport_peers_valid(transport_peers *peers); static void transport_peers_copy(struct site *st, transport_peers *dst, const transport_peers *src); +/* Record address of incoming setup packet; resp. data packet. */ static void transport_setup_msgok(struct site *st, const struct comm_addr *a); static void transport_data_msgok(struct site *st, const struct comm_addr *a); + +/* Initialise the setup addresses. Called before we send the first + * packet in a key exchange. If we are the initiator, as a result of + * resolve completing (or being determined not to be relevant) or an + * incoming PROD; if we are the responder, as a result of the MSG1. */ static bool_t transport_compute_setupinit_peers(struct site *st, - const struct comm_addr *configured_addr /* 0 if none or not found */, - const struct comm_addr *prod_hint_addr /* 0 if none */); -static void transport_record_peer(struct site *st, transport_peers *peers, - const struct comm_addr *addr, const char *m); + const struct comm_addr *configured_addrs /* 0 if none or not found */, + int n_configured_addrs /* 0 if none or not found */, + const struct comm_addr *incoming_packet_addr /* 0 if none */); + +/* Called if we are the responder in a key setup, when the resolve + * completes. transport_compute_setupinit_peers will hvae been called + * earlier. If _complete is called, we are still doing the key setup + * (and we should use the new values for both the rest of the key + * setup and the ongoing data exchange); if _tardy is called, the key + * setup is done (either completed or not) and only the data peers are + * relevant */ +static void transport_resolve_complete(struct site *st, + const struct comm_addr *addrs, int naddrs); +static void transport_resolve_complete_tardy(struct site *st, + const struct comm_addr *addrs, int naddrs); static void transport_xmit(struct site *st, transport_peers *peers, struct buffer_if *buf, bool_t candebug); @@ -545,9 +593,9 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) append_string_xinfo_done(&st->buffer,&xia); buf_append_string(&st->buffer,st->remotename); - memcpy(buf_append(&st->buffer,NONCELEN),st->localN,NONCELEN); + BUF_ADD_OBJ(append,&st->buffer,st->localN); if (type==LABEL_MSG1) return True; - memcpy(buf_append(&st->buffer,NONCELEN),st->remoteN,NONCELEN); + BUF_ADD_OBJ(append,&st->buffer,st->remoteN); if (type==LABEL_MSG2) return True; if (hacky_par_mid_failnow()) return False; @@ -699,7 +747,6 @@ 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); @@ -1143,34 +1190,77 @@ static bool_t send_msg(struct site *st) } } -static void site_resolve_callback(void *sst, struct in_addr *address) +static void site_resolve_callback(void *sst, const struct comm_addr *addrs, + int naddrs, int was_naddrs) { struct site *st=sst; - struct comm_addr ca_buf, *ca_use; st->resolving=False; - if (st->state!=SITE_RESOLVE) { - slog(st,LOG_UNEXPECTED,"site_resolve_callback called unexpectedly"); - return; - } - if (address) { - FILLZERO(ca_buf); - ca_buf.comm=st->comms[0]; - ca_buf.sin.sin_family=AF_INET; - ca_buf.sin.sin_port=htons(st->remoteport); - ca_buf.sin.sin_addr=*address; - ca_use=&ca_buf; + if (naddrs) { + slog(st,LOG_STATE,"resolution of %s completed, %d addrs, eg: %s", + st->address, was_naddrs, comm_addr_to_string(&addrs[0]));; + if (naddrs != was_naddrs) { + slog(st,LOG_SETUP_INIT,"resolution of supplied addresses/names" + " yielded too many results (%d > %d), some ignored", + was_naddrs, naddrs); + } } 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,addrs,naddrs,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 (naddrs) { + /* 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_resolve_complete(st,addrs,naddrs); + } 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 (naddrs) { + slog(st,LOG_SETUP_INIT,"resolution of %s completed tardily," + " updating peer address(es)",st->address); + transport_resolve_complete_tardy(st,addrs,naddrs); + } 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; } } @@ -1183,7 +1273,7 @@ static bool_t initiate_key_setup(struct site *st, cstring_t reason, if (st->address) { slog(st,LOG_SETUP_INIT,"resolving peer address"); return enter_state_resolve(st); - } else if (transport_compute_setupinit_peers(st,0,prod_hint)) { + } else if (transport_compute_setupinit_peers(st,0,0,prod_hint)) { return enter_new_state(st,SITE_SENTMSG1); } slog(st,LOG_SETUP_INIT,"key exchange failed: no address for peer"); @@ -1280,8 +1370,8 @@ static void enter_state_run(struct site *st) st->setup_session_id=0; transport_peers_clear(st,&st->setup_peers); - memset(st->localN,0,NONCELEN); - memset(st->remoteN,0,NONCELEN); + FILLZERO(st->localN); + FILLZERO(st->remoteN); dispose_transform(&st->new_transform); memset(st->dhsecret,0,st->dh->len); memset(st->sharedsecret,0,st->sharedsecretlen); @@ -1295,12 +1385,15 @@ static bool_t ensure_resolving(struct site *st) 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, + st->remoteport,st->comms[0], site_resolve_callback,st); if (!ok) st->resolving=False; @@ -1580,9 +1673,14 @@ 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_compute_setupinit_peers(st,0,0,source); 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"); } @@ -1602,6 +1700,7 @@ 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 " @@ -1640,7 +1739,7 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf, because our peer's forgotten the key */ if (get_uint32(buf->start+4)==st->current.remote_session_id) { bool_t initiated; - initiated = initiate_key_setup(st,"received a NAK",0); + initiated = initiate_key_setup(st,"received a NAK",source); if (!initiated) generate_send_prod(st,source); } else { slog(st,LOG_SEC,"bad incoming NAK"); @@ -1862,12 +1961,14 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, st->mobile_peer_expiry= dict_read_number( dict,"mobile-peer-expiry",False,"site",loc,DEFAULT_MOBILE_PEER_EXPIRY); - st->transport_peers_max= !st->peer_mobile ? 1 : dict_read_number( - dict,"mobile-peers-max",False,"site",loc,DEFAULT_MOBILE_PEERS_MAX); + const char *peerskey= st->peer_mobile + ? "mobile-peers-max" : "static-peers-max"; + st->transport_peers_max= dict_read_number( + dict,peerskey,False,"site",loc, st->address ? 4 : 3); if (st->transport_peers_max<1 || - st->transport_peers_max>=MAX_MOBILE_PEERS_MAX) { - cfgfatal(loc,"site","mobile-peers-max must be in range 1.." - STRING(MAX_MOBILE_PEERS_MAX) "\n"); + st->transport_peers_max>MAX_PEER_ADDRS) { + cfgfatal(loc,"site", "%s must be in range 1.." + STRING(MAX_PEER_ADDRS) "\n", peerskey); } if (st->key_lifetime < DEFAULT(KEY_RENEGOTIATE_GAP)*2) @@ -1987,15 +2088,6 @@ static void transport_peers_debug(struct site *st, transport_peers *dst, } } -static int transport_peer_compar(const void *av, const void *bv) { - const transport_peer *a=av; - const transport_peer *b=bv; - /* put most recent first in the array */ - if (timercmp(&a->last, &b->last, <)) return +1; - if (timercmp(&a->last, &b->last, >)) return -11; - return 0; -} - static void transport_peers_expire(struct site *st, transport_peers *peers) { /* peers must be sorted first */ int previous_peers=peers->npeers; @@ -2009,60 +2101,99 @@ static void transport_peers_expire(struct site *st, transport_peers *peers) { transport_peers_debug(st,peers,"expire", 0,0,0); } -static void transport_record_peer(struct site *st, transport_peers *peers, - const struct comm_addr *addr, const char *m) { - int slot, changed=0; +static bool_t transport_peer_record_one(struct site *st, transport_peers *peers, + const struct comm_addr *ca, + const struct timeval *tv) { + /* returns false if output is full */ + int search; - for (slot=0; slotnpeers; slot++) - if (!memcmp(&peers->peers[slot].addr, addr, sizeof(*addr))) - goto found; + if (peers->npeers >= st->transport_peers_max) + return 0; - changed=1; - if (peers->npeers==st->transport_peers_max) - slot=st->transport_peers_max-1; - else - slot=peers->npeers++; + for (search=0; searchnpeers; search++) + if (comm_addr_equal(&peers->peers[search].addr, ca)) + return 1; + + peers->peers[peers->npeers].addr = *ca; + peers->peers[peers->npeers].last = *tv; + peers->npeers++; + return 1; +} + +static void transport_record_peers(struct site *st, transport_peers *peers, + const struct comm_addr *addrs, int naddrs, + const char *m) { + /* We add addrs into peers. The new entries end up at the front + * and displace entries towards the end (perhaps even off the + * end). Any existing matching entries are moved up to the front. + * + * Caller must first call transport_peers_expire. */ + + if (naddrs==1 && peers->npeers>=1 && + comm_addr_equal(&addrs[0], &peers->peers[0].addr)) { + /* optimisation, also avoids debug for trivial updates */ + peers->peers[0].last = *tv_now; + return; + } - found: - peers->peers[slot].addr=*addr; - peers->peers[slot].last=*tv_now; + int old_npeers=peers->npeers; + transport_peer old_peers[old_npeers]; + COPY_ARRAY(old_peers,peers->peers,old_npeers); - if (peers->npeers>1) - qsort(peers->peers, peers->npeers, - sizeof(*peers->peers), transport_peer_compar); + peers->npeers=0; + int i; + for (i=0; iaddr, &old->last)) + break; + } - if (changed || peers->npeers!=1) - transport_peers_debug(st,peers,m, 1,addr,0); - transport_peers_expire(st, peers); + transport_peers_debug(st,peers,m, naddrs,addrs,0); } -static bool_t transport_compute_setupinit_peers(struct site *st, - const struct comm_addr *configured_addr /* 0 if none or not found */, - const struct comm_addr *prod_hint_addr /* 0 if none */) { +static void transport_expire_record_peers(struct site *st, + transport_peers *peers, + const struct comm_addr *addrs, + int naddrs, const char *m) { + /* Convenience function */ + transport_peers_expire(st,peers); + transport_record_peers(st,peers,addrs,naddrs,m); +} - if (!configured_addr && !prod_hint_addr && +static bool_t transport_compute_setupinit_peers(struct site *st, + const struct comm_addr *configured_addrs /* 0 if none or not found */, + int n_configured_addrs /* 0 if none or not found */, + const struct comm_addr *incoming_packet_addr /* 0 if none */) { + if (!n_configured_addrs && !incoming_packet_addr && !transport_peers_valid(&st->peers)) return False; slog(st,LOG_SETUP_INIT, - "using:%s%s %d old peer address(es)", - configured_addr ? " configured address;" : "", - prod_hint_addr ? " PROD hint address;" : "", + "using: %d configured addr(s);%s %d old peer addrs(es)", + n_configured_addrs, + incoming_packet_addr ? " incoming packet address;" : "", st->peers.npeers); - /* 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 - * one exists; this is as desired. */ + /* Non-mobile peers try addresses until one is plausible. The + * effect is that this code always tries first the configured + * address if supplied, or otherwise the address of the incoming + * PROD, or finally the existing data peer if one exists; this is + * as desired. */ transport_peers_copy(st,&st->setup_peers,&st->peers); + transport_peers_expire(st,&st->setup_peers); - if (prod_hint_addr) - transport_record_peer(st,&st->setup_peers,prod_hint_addr,"prod"); + if (incoming_packet_addr) + transport_record_peers(st,&st->setup_peers, + incoming_packet_addr,1, "incoming"); - if (configured_addr) - transport_record_peer(st,&st->setup_peers,configured_addr,"setupinit"); + if (n_configured_addrs) + transport_record_peers(st,&st->setup_peers, + configured_addrs,n_configured_addrs, "setupinit"); assert(transport_peers_valid(&st->setup_peers)); return True; @@ -2070,11 +2201,11 @@ static bool_t transport_compute_setupinit_peers(struct site *st, static void transport_setup_msgok(struct site *st, const struct comm_addr *a) { if (st->peer_mobile) - transport_record_peer(st,&st->setup_peers,a,"setupmsg"); + transport_expire_record_peers(st,&st->setup_peers,a,1,"setupmsg"); } static void transport_data_msgok(struct site *st, const struct comm_addr *a) { if (st->peer_mobile) - transport_record_peer(st,&st->peers,a,"datamsg"); + transport_expire_record_peers(st,&st->peers,a,1,"datamsg"); } static int transport_peers_valid(transport_peers *peers) { @@ -2087,20 +2218,84 @@ static void transport_peers_clear(struct site *st, transport_peers *peers) { static void transport_peers_copy(struct site *st, transport_peers *dst, const transport_peers *src) { dst->npeers=src->npeers; - memcpy(dst->peers, src->peers, sizeof(*dst->peers) * dst->npeers); + COPY_ARRAY(dst->peers, src->peers, dst->npeers); transport_peers_debug(st,dst,"copy", src->npeers, &src->peers->addr, sizeof(*src->peers)); } +static void transport_resolve_complete(struct site *st, + const struct comm_addr *addrs, + int naddrs) { + transport_expire_record_peers(st,&st->peers,addrs,naddrs, + "resolved data"); + transport_expire_record_peers(st,&st->setup_peers,addrs,naddrs, + "resolved setup"); +} + +static void transport_resolve_complete_tardy(struct site *st, + const struct comm_addr *addrs, + int naddrs) { + transport_expire_record_peers(st,&st->peers,addrs,naddrs, + "resolved tardily"); +} + +static void transport_peers__copy_by_mask(transport_peer *out, int *nout_io, + unsigned mask, + const transport_peers *inp) { + /* out and in->peers may be the same region, or nonoverlapping */ + const transport_peer *in=inp->peers; + int slot; + for (slot=0; slotnpeers; slot++) { + if (!(mask & (1U << slot))) + continue; + if (!(out==in && slot==*nout_io)) + COPY_OBJ(out[*nout_io], in[slot]); + (*nout_io)++; + } +} + void transport_xmit(struct site *st, transport_peers *peers, struct buffer_if *buf, bool_t candebug) { int slot; transport_peers_expire(st, peers); + unsigned failed=0; /* bitmask */ + assert(MAX_PEER_ADDRS < sizeof(unsigned)*CHAR_BIT); + + int nfailed=0; for (slot=0; slotnpeers; slot++) { transport_peer *peer=&peers->peers[slot]; if (candebug) dump_packet(st, buf, &peer->addr, False); - peer->addr.comm->sendmsg(peer->addr.comm->st, buf, &peer->addr); + bool_t ok = + peer->addr.comm->sendmsg(peer->addr.comm->st, buf, &peer->addr); + if (!ok) { + failed |= 1U << slot; + nfailed++; + } + if (ok && !st->peer_mobile) + break; + } + /* Now we need to demote/delete failing addrs: if we are mobile we + * merely demote them; otherwise we delete them. */ + if (st->local_mobile) { + unsigned expected = ((1U << nfailed)-1) << (peers->npeers-nfailed); + /* `expected' has all the failures at the end already */ + if (failed != expected) { + int fslot=0; + transport_peer failedpeers[nfailed]; + transport_peers__copy_by_mask(failedpeers, &fslot, failed,peers); + assert(fslot == nfailed); + int wslot=0; + transport_peers__copy_by_mask(peers->peers,&wslot,~failed,peers); + assert(wslot+nfailed == peers->npeers); + COPY_ARRAY(peers->peers+wslot, failedpeers, nfailed); + } + } else { + if (failed && peers->npeers > 1) { + int wslot=0; + transport_peers__copy_by_mask(peers->peers,&wslot,~failed,peers); + peers->npeers=wslot; + } } }