--- gvpe/src/vpn_dns.C 2005/03/02 05:49:31 1.4 +++ gvpe/src/vpn_dns.C 2005/03/03 07:24:57 1.5 @@ -44,10 +44,16 @@ #define MIN_RETRY 1. #define MAX_RETRY 60. -#define MAX_OUTSTANDING 10 // max. outstanding requests +#define MAX_OUTSTANDING 40 // max. outstanding requests #define MAX_WINDOW 100 // max. for MAX_OUTSTANDING -#define MAX_RATE 1 // requests/s -#define MAX_BACKLOG (10*1024) // size of protocol backlog +#define MAX_RATE 1000 // requests/s +#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE + +#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well +// 240 leaves about 4 bytes of server reply data +// every two request byte sless give room for one reply byte + +#define SEQNO_MASK 0xffff /* @@ -86,7 +92,7 @@ dns64 (); } dns64; -const char dns64::encode_chars[64 + 1] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-"; +const char dns64::encode_chars[64 + 1] = "_4B9dLphHzrqQmGjkTbJt5svlZX8xSaReEYfwKgF1DP2W6NyVOU70IouACcMn3i-"; s8 dns64::decode_chars[256]; dns64::dns64 () @@ -131,7 +137,7 @@ s8 chr = decode_chars [(u8)*src++]; if (!chr) - break; + continue; accum <<= 6; accum |= chr - 1; @@ -161,6 +167,7 @@ bool empty () { return !fill; } int size () { return fill; } + bool put (u8 *data, unsigned int datalen); bool put (vpn_packet *pkt); vpn_packet *get (); @@ -187,6 +194,16 @@ memmove (data, data + count, fill -= count); } +bool byte_stream::put (u8 *data, unsigned int datalen) +{ + if (maxsize - fill < datalen) + return false; + + memcpy (this->data + fill, data, datalen); fill += datalen; + + return true; +} + bool byte_stream::put (vpn_packet *pkt) { if (maxsize - fill < pkt->len + 2) @@ -204,10 +221,17 @@ { int len = (data [0] << 8) | data [1]; + printf ("get len %d, fill %d\n", len, fill);//D + + if (len > MAXSIZE && fill >= 2) + abort (); // TODO handle this gracefully, connection reset + if (fill < len + 2) return 0; vpn_packet *pkt = new vpn_packet; + + pkt->len = len; memcpy (&((*pkt)[0]), data + 2, len); remove (len + 2); @@ -224,6 +248,7 @@ #define FLAG_TC ( 1 << 9) #define FLAG_RD ( 1 << 8) #define FLAG_RA ( 1 << 7) +#define FLAG_AUTH ( 1 << 5) #define FLAG_RCODE_MASK (15 << 0) #define FLAG_RCODE_OK ( 0 << 0) #define FLAG_RCODE_FORMERR ( 1 << 0) @@ -232,7 +257,7 @@ #define FLAG_RCODE_REFUSED ( 5 << 0) #define DEFAULT_CLIENT_FLAGS (FLAG_QUERY | FLAG_OP_QUERY | FLAG_RD) -#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE | FLAG_OP_QUERY | FLAG_AA | FLAG_RD) +#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE | FLAG_OP_QUERY | FLAG_AA | FLAG_RD | FLAG_RA) struct dns_packet : net_packet { @@ -287,17 +312,27 @@ tstamp next; int retry; connection *conn; + int seqno; - dns_req (connection *c, int seqno, byte_stream *stream); + dns_req (connection *c); + void gen_stream_req (int seqno, byte_stream *stream); }; -struct dns_rep +static u16 dns_id = 12098; // TODO: should be per-vpn + +static u16 next_id () { -}; + // the simplest lsfr with periodicity 65535 i could find + dns_id = (dns_id << 1) + | (((dns_id >> 1) + ^ (dns_id >> 2) + ^ (dns_id >> 4) + ^ (dns_id >> 15)) & 1); -static u16 dns_id; // TODO: should be per-vpn + return dns_id; +} -dns_req::dns_req (connection *c, int seqno, byte_stream *stream) +dns_req::dns_req (connection *c) : conn (c) { next = 0; @@ -305,49 +340,49 @@ pkt = new dns_packet; - pkt->id = dns_id++; - pkt->flags = DEFAULT_CLIENT_FLAGS; + pkt->id = next_id (); +} + +void dns_req::gen_stream_req (int seqno, byte_stream *stream) +{ + this->seqno = seqno; + + pkt->flags = htons (DEFAULT_CLIENT_FLAGS); pkt->qdcount = htons (1); - pkt->ancount = 0; - pkt->nscount = 0; - pkt->arcount = 0; int offs = 6*2; - int dlen = 255 - strlen (THISNODE->domain) - 1; // here we always have room for the max. label length + int dlen = MAX_DOMAIN_SIZE - strlen (THISNODE->domain) - 2; + // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, + // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra - u8 lbl[64]; //D - char enc[65]; - int lbllen = 3; - lbl[0] = c->conf->id; //D - lbl[1] = seqno >> 8; //D - lbl[2] = seqno; //D + u8 data[256]; //TODO - while (dlen > 0) - { - int sndlen = dlen; + data[0] = THISNODE->id; //TODO + data[1] = seqno >> 8; //TODO + data[2] = seqno; //TODO - if (sndlen + lbllen > dns64::decode_len (MAX_LBL_SIZE)) - sndlen = dns64::decode_len (MAX_LBL_SIZE) - lbllen; + int datalen = dns64::decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE) - 3; - if (sndlen > stream->size ()) - sndlen = stream->size (); + if (datalen > stream->size ()) + datalen = stream->size (); - if (sndlen + lbllen == 0) - break; + char enc[256], *encp = enc; + + memcpy (data + 3, stream->begin (), datalen); + int enclen = dns64::encode (enc, data, datalen + 3); + stream->remove (datalen); + + while (enclen) + { + int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; - memcpy (lbl + lbllen, stream->begin (), sndlen); - stream->remove (sndlen); - lbllen += sndlen; - - dns64::encode (enc, lbl, lbllen); - - int elen = dns64::encode_len (lbllen); - (*pkt)[offs++] = elen; - memcpy (&((*pkt)[offs]), enc, elen); - offs += elen; - dlen -= elen + 1; + (*pkt)[offs++] = lbllen; + memcpy (pkt->at (offs), encp, lbllen); - lbllen = 0; + offs += lbllen; + encp += lbllen; + + enclen -= lbllen; } const char *suffix = THISNODE->domain; @@ -377,8 +412,30 @@ (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; pkt->len = offs; +} + +struct dns_rcv +{ + int seqno; + dns_packet *pkt; // reply packet + u8 data [MAXSIZE]; // actually part of the reply packet... + int datalen; + + dns_rcv (int seqno, dns_packet *req, u8 *data, int datalen); + ~dns_rcv (); +}; + +dns_rcv::dns_rcv (int seqno, dns_packet *req, u8 *data, int datalen) +: seqno (seqno), pkt (new dns_packet), datalen (datalen) +{ + memcpy (this->data, data, datalen); + pkt->len = req->len; + memcpy (pkt->at (0), req->at (0), req->len); +} - c->vpn->dns_sndpq.push_back (this); +dns_rcv::~dns_rcv () +{ + delete pkt; } ///////////////////////////////////////////////////////////////////////////// @@ -392,6 +449,47 @@ u8 flags1, flags2; }; +void connection::dnsv4_receive_rep (struct dns_rcv *r) +{ + dns_rcvpq.push_back (r); + + redo: + + for (vector::iterator i = dns_rcvpq.begin (); + i != dns_rcvpq.end (); + ++i) + if (dns_rcvseq == (*i)->seqno) + { + dns_rcv *r = *i; + + dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK; + + if (!dns_snddq && !dns_rcvdq) + { + dns_rcvdq = new byte_stream (MAX_BACKLOG * 2); + dns_snddq = new byte_stream (MAX_BACKLOG); + + dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4); + } + + if (!dns_rcvdq->put (r->data, r->datalen)) + abort (); // MUST never overflow, can be caused by data corruption, TODO + + while (vpn_packet *pkt = dns_rcvdq->get ()) + { + sockinfo si; + si.host = 0; si.port = 0; si.prot = PROT_DNSv4; + + vpn->recv_vpn_packet (pkt, si); + } + } + else if ((u32)dns_rcvseq - MAX_WINDOW - (u32)(*i)->seqno < MAX_WINDOW * 2) + { + dns_rcvpq.erase (i); + goto redo; + } +} + dns_packet * vpn::dnsv4_server (dns_packet *pkt) { @@ -408,9 +506,6 @@ char qname[MAXSIZE]; int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs); - printf ("rcvd packet len %d, id%04x flags%04x q%04x a%04x n%04x a%04x <%s>\n", pkt->len, - pkt->id, flags, pkt->qdcount, pkt->ancount, pkt->nscount, pkt->arcount, qname);//D - u16 qtype = (*pkt) [offs++] << 8; qtype |= (*pkt) [offs++]; u16 qclass = (*pkt) [offs++] << 8; qclass |= (*pkt) [offs++]; @@ -428,66 +523,87 @@ && qlen > dlen + 1 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) { - // correct class, domain, parse + // correct class, domain: parse u8 data[MAXSIZE]; int datalen = dns64::decode (data, qname, qlen - dlen - 1); - for (int i = 0; i < datalen; i++) - printf ("%02x ", data[i]); - printf ("\n"); + int client = data[0]; + int seqno = ((data[1] << 8) | data[2]) & SEQNO_MASK; - + if (0 < client && client <= conns.size ()) + { + connection *c = conns [client - 1]; + for (vector::iterator i = c->dns_rcvpq.begin (); + i != c->dns_rcvpq.end (); + ++i) + if ((*i)->seqno == seqno) + { + // already seen that request, just reply with the original reply + dns_rcv *r = *i; -#if 0 - // now generate reply - rep->ancount = htons (1); // one answer RR - rep->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); + offs = r->pkt->len; + memcpy (pkt->at (0), r->pkt->at (0), offs); + goto duplicate_request; + } - (*rep) [offs++] = 0xc0; - (*rep) [offs++] = 6 * 2; // same as in query section + // new packet, queue + c->dnsv4_receive_rep (new dns_rcv (seqno, pkt, data + 3, datalen - 3)); - (*rep) [offs++] = RR_TYPE_TXT >> 8; (*rep) [offs++] = RR_TYPE_TXT; - (*rep) [offs++] = RR_CLASS_IN >> 8; (*rep) [offs++] = RR_CLASS_IN; + // now generate reply + pkt->ancount = htons (1); // one answer RR + pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); - (*rep) [offs++] = 0; (*rep) [offs++] = 0; - (*rep) [offs++] = 0; (*rep) [offs++] = 0; // TTL + (*pkt) [offs++] = 0xc0; + (*pkt) [offs++] = 6 * 2; // same as in query section - int dlen = MAX_PKT_SIZE - offs - 2; + (*pkt) [offs++] = RR_TYPE_TXT >> 8; (*pkt) [offs++] = RR_TYPE_TXT; + (*pkt) [offs++] = RR_CLASS_IN >> 8; (*pkt) [offs++] = RR_CLASS_IN; - printf ("we have room for %d bytes\n", dlen); + (*pkt) [offs++] = 0; (*pkt) [offs++] = 0; + (*pkt) [offs++] = 0; (*pkt) [offs++] = 0; // TTL - int rdlen_offs = offs += 2; + int dlen = MAX_PKT_SIZE - offs - 2; - u8 txt[255]; - txt[0] = 0; - txt[1] = 0; + // bind doesn't compress well, so reduce further by one label length + dlen -= qlen; - int txtlen = 2; + int rdlen_offs = offs += 2; - while (dlen > 1) - { - int sndlen = --dlen; + while (c->dns_snddq + && !c->dns_snddq->empty () + && dlen > 1) + { + int txtlen = dlen <= 255 ? dlen - 1 : 255; - if (sndlen + txtlen > 255) - sndlen = 255 - txtlen; + if (txtlen > c->dns_snddq->size ()) + txtlen = c->dns_snddq->size (); - sndlen = 0; + (*pkt)[offs++] = txtlen; + memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen); + offs += txtlen; + c->dns_snddq->remove (txtlen); - (*rep)[offs++] = sndlen + txtlen; - memcpy (&((*rep)[offs]), txt, txtlen); - offs += txtlen; + dlen -= txtlen + 1; + } - //if (sndlen + txtlen > dns_snddq. - } + // avoid empty TXT rdata + if (offs == rdlen_offs) + (*pkt)[offs++] = 0; - int rdlen = offs - rdlen_offs; + int rdlen = offs - rdlen_offs; - (*rep) [rdlen_offs - 2] = rdlen >> 8; - (*rep) [rdlen_offs - 1] = rdlen; -#endif + (*pkt) [rdlen_offs - 2] = rdlen >> 8; + (*pkt) [rdlen_offs - 1] = rdlen; + + duplicate_request: ; + } + else + pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); } } + else + offs = pkt->len; pkt->len = offs; return pkt; @@ -502,13 +618,16 @@ pkt->qdcount = ntohs (pkt->qdcount); pkt->ancount = ntohs (pkt->ancount); + // go through our request list and find the corresponding request for (vector::iterator i = dns_sndpq.begin (); i != dns_sndpq.end (); ++i) if ((*i)->pkt->id == pkt->id) { connection *c = (*i)->conn; - printf ("GOT RESPONSE id %x %p\n", pkt->id, c);//D + int seqno = (*i)->seqno; + u8 data[MAXSIZE], *datap = data; + delete *i; dns_sndpq.erase (i); @@ -535,19 +654,41 @@ u16 rdlen = (*pkt) [offs++] << 8; rdlen |= (*pkt) [offs++]; - printf ("REPLY %d:%d TTL %d RD %d\n", qtype, qclass, ttl, rdlen); - - offs += rdlen; - - if (MAXSIZE - offs < rdlen) + if (rdlen <= MAXSIZE - offs) { // decode bytes, finally + + while (rdlen) + { + int txtlen = (*pkt) [offs++]; + + assert (txtlen + offs < MAXSIZE - 1); + + memcpy (datap, pkt->at (offs), txtlen); + datap += txtlen; offs += txtlen; + + rdlen -= txtlen + 1; + } + } + } } + if (datap != data) + printf ("%02x %02x %02x %02x\n", + data[0], + data[1], + data[2], + data[3]); + + printf ("recv %d,%d\n", pkt->id, seqno, datap - data);//D + c->dnsv4_receive_rep (new dns_rcv (seqno, pkt, data, datap - data)); + break; } + + delete pkt; } void @@ -562,13 +703,21 @@ pkt->len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); if (pkt->len > 0) - if (THISNODE->dns_port) - { - pkt = dnsv4_server (pkt); - sendto (w.fd, &((*pkt)[0]), pkt->len, 0, (sockaddr *)&sa, sa_len); - } - else - dnsv4_client (pkt); + { + if (pkt->flags & htons (FLAG_TC)) + { + slog (L_WARN, _("DNS request/response truncated, check protocol settings.")); + //TODO connection reset + } + + if (THISNODE->dns_port) + { + pkt = dnsv4_server (pkt); + sendto (w.fd, &((*pkt)[0]), pkt->len, 0, (sockaddr *)&sa, sa_len); + } + else + dnsv4_client (pkt); + } } } @@ -581,7 +730,7 @@ dns_rcvdq = new byte_stream (MAX_BACKLOG * 2); dns_snddq = new byte_stream (MAX_BACKLOG); - dns_rcvseq = dns_sndseq = 0; + //dns_rcvseq = dns_sndseq = 0; dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4); } @@ -590,7 +739,7 @@ return false; // start timer if neccessary - if (!dnsv4_tw.active) + if (!THISNODE->dns_port && !dnsv4_tw.active) dnsv4_cb (dnsv4_tw); return true; @@ -603,8 +752,6 @@ tstamp next = NOW + 60; dns_req *send = 0; - slog (L_NOISE, _("dnsv4, %d packets in send queue\n"), vpn->dns_sndpq.size ()); - for (vector::iterator i = vpn->dns_sndpq.begin (); i != vpn->dns_sndpq.end (); ++i) @@ -617,7 +764,8 @@ { send = r; - slog (L_NOISE, _("dnsv4, send req %d\n"), r->pkt->id); + if (r->retry)//D + printf ("req %d, retry %d\n", r->pkt->id, r->retry); r->retry++; r->next = NOW + r->retry; } @@ -629,7 +777,13 @@ if (!send && vpn->dns_sndpq.size () < MAX_OUTSTANDING) - send = new dns_req (this, dns_sndseq++, dns_snddq); + { + send = new dns_req (this); + send->gen_stream_req (dns_sndseq, dns_snddq); + vpn->dns_sndpq.push_back (send); + + dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK; + } tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);