/*************************************************************************** * EchoServer.cc -- * * * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * * The Nmap Security Scanner is (C) 1996-2012 Insecure.Com LLC. Nmap is * * also a registered trademark of Insecure.Com LLC. This program is free * * software; you may redistribute and/or modify it under the terms of the * * GNU General Public License as published by the Free Software * * Foundation; Version 2 with the clarifications and exceptions described * * below. This guarantees your right to use, modify, and redistribute * * this software under certain conditions. If you wish to embed Nmap * * technology into proprietary software, we sell alternative licenses * * (contact sales@insecure.com). Dozens of software vendors already * * license Nmap technology such as host discovery, port scanning, OS * * detection, version detection, and the Nmap Scripting Engine. * * * * Note that the GPL places important restrictions on "derived works", yet * * it does not provide a detailed definition of that term. To avoid * * misunderstandings, we interpret that term as broadly as copyright law * * allows. For example, we consider an application to constitute a * * "derivative work" for the purpose of this license if it does any of the * * following: * * o Integrates source code from Nmap * * o Reads or includes Nmap copyrighted data files, such as * * nmap-os-db or nmap-service-probes. * * o Executes Nmap and parses the results (as opposed to typical shell or * * execution-menu apps, which simply display raw Nmap output and so are * * not derivative works.) * * o Integrates/includes/aggregates Nmap into a proprietary executable * * installer, such as those produced by InstallShield. * * o Links to a library or executes a program that does any of the above * * * * The term "Nmap" should be taken to also include any portions or derived * * works of Nmap, as well as other software we distribute under this * * license such as Zenmap, Ncat, and Nping. This list is not exclusive, * * but is meant to clarify our interpretation of derived works with some * * common examples. Our interpretation applies only to Nmap--we don't * * speak for other people's GPL works. * * * * If you have any questions about the GPL licensing restrictions on using * * Nmap in non-GPL works, we would be happy to help. As mentioned above, * * we also offer alternative license to integrate Nmap into proprietary * * applications and appliances. These contracts have been sold to dozens * * of software vendors, and generally include a perpetual license as well * * as providing for priority support and updates. They also fund the * * continued development of Nmap. Please email sales@insecure.com for * * further information. * * * * As a special exception to the GPL terms, Insecure.Com LLC grants * * permission to link the code of this program with any version of the * * OpenSSL library which is distributed under a license identical to that * * listed in the included docs/licenses/OpenSSL.txt file, and distribute * * linked combinations including the two. You must obey the GNU GPL in all * * respects for all of the code used other than OpenSSL. If you modify * * this file, you may extend this exception to your version of the file, * * but you are not obligated to do so. * * * * If you received these files with a written license agreement or * * contract stating terms other than the terms above, then that * * alternative license agreement takes precedence over these comments. * * * * Source is provided to this software because we believe users have a * * right to know exactly what a program is going to do before they run it. * * This also allows you to audit the software for security holes (none * * have been found so far). * * * * Source code also allows you to port Nmap to new platforms, fix bugs, * * and add new features. You are highly encouraged to send your changes * * to the dev@nmap.org mailing list for possible incorporation into the * * main distribution. By sending these changes to Fyodor or one of the * * Insecure.Org development mailing lists, or checking them into the Nmap * * source code repository, it is understood (unless you specify otherwise) * * that you are offering the Nmap Project (Insecure.Com LLC) the * * unlimited, non-exclusive right to reuse, modify, and relicense the * * code. Nmap will always be available Open Source, but this is important * * because the inability to relicense code has caused devastating problems * * for other Free Software projects (such as KDE and NASM). We also * * occasionally relicense the code to third parties as discussed above. * * If you wish to specify special license conditions of your * * contributions, just say so when you send them. * * * * This program is distributed in the hope that it will be useful, but * * WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Nmap * * license file for more details (it's in a COPYING file included with * * Nmap, and also available from https://svn.nmap.org/nmap/COPYING * * * ***************************************************************************/ #include "nping.h" #include "EchoServer.h" #include "EchoHeader.h" #include "NEPContext.h" #include #include "nsock.h" #include "output.h" #include "NpingOps.h" #include "ProbeMode.h" #include extern NpingOps o; extern EchoServer es; EchoServer::EchoServer() { this->reset(); } /* End of EchoServer constructor */ EchoServer::~EchoServer() { } /* End of EchoServer destructor */ /** Sets every attribute to its default value- */ void EchoServer::reset() { this->client_ctx.clear(); this->client_id_count=-1; } /* End of reset() */ /** Adds a new client context object to the server context list */ int EchoServer::addClientContext(NEPContext ctx){ outPrint(DBG_4, "%s(ctx->id=%d)", __func__, ctx.getIdentifier()); this->client_ctx.push_back(ctx); return OP_SUCCESS; } /* End of addClientContext() */ /** Looks up the context of a given client, based on the supplied client ID. * On success, it returns a pointer to the client's context object. NULL is * returned when no context could be found. */ NEPContext *EchoServer::getClientContext(clientid_t clnt){ outPrint(DBG_4, "%s(%d) %lu", __func__, clnt, (unsigned long)this->client_ctx.size()); for(unsigned int i=0; iclient_ctx.size(); i++){ if(this->client_ctx[i].getIdentifier() == clnt ){ outPrint(DBG_3, "Found client with ID #%d at p%d. Total clients %lu", clnt, i, (unsigned long)this->client_ctx.size()); return &(this->client_ctx[i]); } } outPrint(DBG_3, "No client with ID #%d was found. Total clients %lu", clnt, (unsigned long)this->client_ctx.size()); return NULL; } /* End of getClientContext() */ /** Looks up the context of a given client, based on the supplied nsock IOD. * On success, it returns a pointer to the client's context object. NULL is * returned when no context could be found. */ NEPContext *EchoServer::getClientContext(nsock_iod iod){ outPrint(DBG_4, "%s()", __func__); clientid_t *id=NULL; if( (id=(clientid_t *)nsi_getud(iod))==NULL ) return NULL; else return this->getClientContext(*id); } /* End of getClientContext() */ /** Deletes context information associated with a given client. Returns * OP_SUCCESS if the context object was successfully deleted or OP_FAILURE if * the context could not be found. */ int EchoServer::destroyClientContext(clientid_t clnt){ bool deleted=false; vector::iterator it; /* Iterate through the context array and delete the one that belongs to clnt */ for ( it=this->client_ctx.begin(); itclient_ctx.end(); it++){ if(it->getIdentifier()==clnt){ this->client_ctx.erase(it); deleted=true; break; } } return (deleted) ? OP_SUCCESS : OP_FAILURE; } /* End of destroyClientContext() */ /** Returns the Nsock IOD associated with a given client ID. */ nsock_iod EchoServer::getClientNsockIOD(clientid_t clnt){ outPrint(DBG_4, "%s(%d)", __func__, clnt); NEPContext *ctx; if((ctx=this->getClientContext(clnt))==NULL ) return NULL; else return ctx->getNsockIOD(); } /* End of getClientNsockIOD() */ /** Generates a new client identifier. This is used internally by the echo * server, but this value is never sent over the wire (it has nothing to do * with the NEP protocol). Each call to getNewClientID() generates a new * identifier, so it should only be called once per client session. * Warning: This code checks for an overflow and wraps the client id count back * to zero if necessary. A given execution of a server should be able to handle * 4,294,967,296 client sessions. Practically there is no way to achieve that * number (it would be something like receiving one client session per second * for 136 years, so relax!) However, it should be noted that this * implementation makes no effort to handle re-used client identifiers, so * there is a tiny chance that after the 4,294,967,296th client, the assigned * number conflicts with an active session ;-) */ clientid_t EchoServer::getNewClientID(){ outPrint(DBG_4, "%s()", __func__); if(this->client_id_count==0xFFFF) /* Wrap back to zero. */ this->client_id_count=0; else this->client_id_count++; return this->client_id_count; } /* End of getNewClientID() */ /** Returns a socket suitable to be passed to accept() */ int EchoServer::nep_listen_socket(){ outPrint(DBG_4, "%s()", __func__); int one=1; /**< Dummy var for setsockopt() call */ int master_sd=-1; /**< Master socket. Server listens on it */ struct sockaddr_in server_addr4; /**< For our own IPv4 address */ struct sockaddr_in6 server_addr6; /**< For our own IPv6 address */ int port = o.getEchoPort(); /* Ignore SIGPIPE signal, received when a client disconnects suddenly and *data is sent to it before noticing. */ #ifndef WIN32 signal(SIGPIPE, SIG_IGN); #endif /* AF_INET6 */ if( o.ipv6() ){ /* Obtain a regular TCP socket for IPv6 */ if( (master_sd=socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP))<0 ) outFatal(QT_3, "Could not obtain AF_INET/SOCK_STREAM/IPPROTO_TCP socket"); /* Set SO_REUSEADDR on socket so the bind does not fail if we had used * this port in a previous execution, not long ago. */ if( setsockopt(master_sd, SOL_SOCKET, SO_REUSEADDR, (char *) &one, sizeof(int))!=0 ) outError(QT_3, "Failed to set SO_REUSEADDR on master socket."); memset(&server_addr6, 0, sizeof(struct sockaddr_in6)); server_addr6.sin6_addr = (o.spoofSource()) ? o.getIPv6SourceAddress() : in6addr_any; server_addr6.sin6_family = AF_INET6; server_addr6.sin6_port = htons(port); server_addr6.sin6_flowinfo = 0; #ifdef HAVE_SOCKADDR_IN6_SIN6_LEN server_addr6.sin6_len = sizeof(struct sockaddr_in6); #endif /* Bind to local address and the specified port */ if( bind(master_sd, (struct sockaddr *)&server_addr6, sizeof(server_addr6)) != 0 ){ outError(QT_3, "Failed to bind to source address %s. Trying to bind to port %d...", IPtoa(server_addr6.sin6_addr), port); /* If the bind failed for the supplied address, just try again with in6addr_any */ if( o.spoofSource() ){ server_addr6.sin6_addr = in6addr_any; if( bind(master_sd, (struct sockaddr *)&server_addr6, sizeof(server_addr6)) != 0 ){ outFatal(QT_3, "Could not bind to port %d (%s).", port, strerror(errno)); }else{ outPrint(VB_1, "Server bound to port %d", port); } } }else{ outPrint(VB_1, "Server bound to %s:%d", IPtoa(server_addr6.sin6_addr), port); } /* AF_INET */ }else{ /* Obtain a regular TCP socket for IPv4 */ if( (master_sd=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP))<0 ) outFatal(QT_3, "Could not obtain AF_INET/SOCK_STREAM/IPPROTO_TCP socket"); /* Set SO_REUSEADDR on socket so the bind does not fail if we had used * this port in a previous execution, not long ago. */ if( setsockopt(master_sd, SOL_SOCKET, SO_REUSEADDR, (char *) &one, sizeof(int))!=0 ) outError(QT_3, "Failed to set SO_REUSEADDR on master socket."); memset(&server_addr4, 0, sizeof(struct sockaddr_in)); server_addr4.sin_family = AF_INET; server_addr4.sin_port = htons(port); server_addr4.sin_addr.s_addr = (o.spoofSource()) ? o.getIPv4SourceAddress().s_addr : INADDR_ANY; #ifdef HAVE_SOCKADDR_IN_SIN_LEN server_addr4.sin_len = sizeof(struct sockaddr_in); #endif /* Bind to local address and the specified port */ if( bind(master_sd, (struct sockaddr *)&server_addr4, sizeof(server_addr4)) != 0 ){ outError(QT_3, "Failed to bind to source address %s. Trying to bind to port %d...", IPtoa(server_addr4.sin_addr), port); /* If the bind failed for the supplied address, just try again with in6addr_any */ if( o.spoofSource() ){ server_addr4.sin_addr.s_addr=INADDR_ANY; if( bind(master_sd, (struct sockaddr *)&server_addr4, sizeof(server_addr4)) != 0 ){ outFatal(QT_3, "Could not bind to port %d (%s).", port, strerror(errno)); }else{ outPrint(VB_1, "Server bound to port %d", port); } } }else{ outPrint(VB_1, "Server bound to %s:%d", IPtoa(server_addr4.sin_addr), port); } } /* Listen for incoming TCP connections... */ if( listen(master_sd, LISTEN_QUEUE_SIZE) != 0 ){ outFatal(QT_3, "[E] Failed to listen() on port %d (%s)", port, strerror(errno)); } return master_sd; } /* End of nep_listen() */ /* Weighting factors */ #define FACTOR_IPv4_TOS 1.0 #define FACTOR_IPv4_PROTO 0.9 #define FACTOR_IPv4_ID 2.5 #define FACTOR_IPv4_FRAGOFF 1.0 #define FACTOR_IPv6_TCLASS 1.0 #define FACTOR_IPv6_FLOW 2.5 #define FACTOR_IPv6_NHDR 0.9 #define FACTOR_TCP_SPORT 1.5 #define FACTOR_TCP_DPORT 1.0 #define FACTOR_TCP_SEQ 2.0 #define FACTOR_TCP_ACK 1.0 #define FACTOR_TCP_FLAGS 1.0 #define FACTOR_TCP_WIN 1.0 #define FACTOR_TCP_URP 1.0 #define FACTOR_ICMP_TYPE 1.0 #define FACTOR_ICMP_CODE 1.0 #define FACTOR_UDP_SPORT 1.0 #define FACTOR_UDP_DPORT 1.0 #define FACTOR_UDP_LEN 1.0 #define FACTOR_PAYLOAD_MAGIC 1.0 #define ZERO_PENALTY 0.3 #define MIN_ACCEPTABLE_SCORE_TCP 10.0 #define MIN_ACCEPTABLE_SCORE_UDP 8.0 #define MIN_ACCEPTABLE_SCORE_ICMP 6.0 clientid_t EchoServer::nep_match_headers(IPv4Header *ip4, IPv6Header *ip6, TCPHeader *tcp, UDPHeader *udp, ICMPv4Header *icmp4, RawData *payload){ outPrint(DBG_4, "%s(%p,%p,%p,%p,%p,%p)", __func__, ip4, ip6, tcp, udp, icmp4, payload); unsigned int i=0, k=0; u8 *buff=NULL; int bufflen=-1; NEPContext *ctx; fspec_t *fspec; float current_score=0; float candidate_score=-1; float minimum_score=0; clientid_t candidate=-1; /* Iterate through the list of connected clients */ for(i=0; iclient_ctx.size(); i++ ){ current_score=0; ctx=&(this->client_ctx[i]); outPrint(DBG_2, "%s() Trying to match packet against client #%d", __func__, ctx->getIdentifier()); if( ctx->ready() ){ /* Iterate through client's list of packet field specifiers */ for(k=0; (fspec=ctx->getClientFieldSpec(k))!=NULL; k++){ switch(fspec->field){ case PSPEC_IPv4_TOS: if(ip4==NULL)break; outPrint(DBG_3, "%s() Trying to match IP TOS", __func__); if( ip4->getTOS()==fspec->value[0] ){ outPrint(DBG_3, "[Match] IP TOS=%02x", ip4->getTOS()); current_score += 1 * FACTOR_IPv4_TOS * ((ip4->getTOS()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_IPv4_PROTO: if(ip4==NULL)break; outPrint(DBG_3, "%s() Trying to match IP Next Protocol", __func__); if( ip4->getNextProto()==fspec->value[0] ){ outPrint(DBG_3, "[Match] IP Proto=%02x", ip4->getNextProto()); current_score += 1 * FACTOR_IPv4_PROTO; } break; case PSPEC_IPv4_ID: if(ip4==NULL)break; outPrint(DBG_3, "%s() Trying to match IP Identification", __func__); if( ip4->getIdentification()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] IP Id=%u", ip4->getIdentification()); current_score += 2 * FACTOR_IPv4_ID; } break; case PSPEC_IPv4_FRAGOFF: if(ip4==NULL)break; outPrint(DBG_3, "%s() Trying to match IP Fragment offset", __func__); if( ip4->getFragOffset()==ntohs( *((u16 *)fspec->value)) ){ outPrint(DBG_3, "[Match] IP FragOff=%u", ip4->getFragOffset() ); current_score += 2 * FACTOR_IPv4_FRAGOFF * ((ip4->getFragOffset()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_IPv6_TCLASS: if(ip6==NULL)break; outPrint(DBG_3, "%s() Trying to match IPv6 Traffic Class", __func__); if( ip6->getTrafficClass()==fspec->value[0] ){ outPrint(DBG_3, "[Match] IPv6 TClass=%u", ip6->getTrafficClass() ); current_score += 1 * FACTOR_IPv6_TCLASS * ((ip6->getTrafficClass()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_IPv6_FLOW: if(ip6==NULL)break; outPrint(DBG_3, "%s() Trying to match IPv6 Flow Label", __func__); if( ip6->getFlowLabel()==ntohl( *((u32 *)fspec->value)) ){ outPrint(DBG_3, "[Match] IPv6 Flow=%lu", (long unsigned)ip6->getFlowLabel() ); current_score += 3 * FACTOR_IPv6_FLOW * ((ip6->getFlowLabel()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_IPv6_NHDR: if(ip6==NULL)break; outPrint(DBG_3, "%s() Trying to match IPv6 Next Header", __func__); if( ip6->getNextHeader()==fspec->value[0] ){ outPrint(DBG_3, "[Match] IPv6 NextHdr=%02x", ip6->getNextHeader()); current_score += 1 * FACTOR_IPv6_NHDR; } break; case PSPEC_TCP_SPORT: if(tcp==NULL)break; outPrint(DBG_3, "%s() Trying to match TCP Source Port", __func__); if( tcp->getSourcePort()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] TCP Src=%u", tcp->getSourcePort()); current_score += 2 * FACTOR_TCP_SPORT; } break; case PSPEC_TCP_DPORT: if(tcp==NULL)break; outPrint(DBG_3, "%s() Trying to match TCP Destination Port", __func__); if( tcp->getDestinationPort()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] TCP Dst=%u", tcp->getDestinationPort()); current_score += 2 * FACTOR_TCP_DPORT; } break; case PSPEC_TCP_SEQ: if(tcp==NULL)break; outPrint(DBG_3, "%s() Trying to match TCP Sequence Number", __func__); if( tcp->getSeq()==ntohl( *((u32 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] TCP Seq=%u", tcp->getSeq()); current_score += 4 * FACTOR_TCP_SEQ * ((tcp->getSeq()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_TCP_ACK: if(tcp==NULL)break; outPrint(DBG_3, "%s() Trying to match TCP Acknowledgment", __func__); if( tcp->getAck()==ntohl( *((u32 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] TCP Ack=%u", tcp->getAck()); current_score += 4 * FACTOR_TCP_ACK * ((tcp->getAck()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_TCP_FLAGS: if(tcp==NULL)break; if( tcp->getFlags()==fspec->value[0] ){ outPrint(DBG_3, "%s() Trying to match TCP Flags", __func__); outPrint(DBG_3, "[Match] TCP Flags=%02x", tcp->getFlags()); current_score += 1 * FACTOR_TCP_FLAGS; } break; case PSPEC_TCP_WIN: if(tcp==NULL)break; outPrint(DBG_3, "%s() Trying to match TCP Window", __func__); if( tcp->getWindow()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] TCP Win=%u", tcp->getWindow()); current_score += 2 * FACTOR_TCP_WIN * ((tcp->getWindow()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_TCP_URP: if(tcp==NULL)break; outPrint(DBG_3, "%s() Trying to match TCP Urgent Pointer", __func__); if( tcp->getUrgPointer()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] TCP Win=%u", tcp->getUrgPointer()); current_score += 2 * FACTOR_TCP_URP * ((tcp->getUrgPointer()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_ICMP_TYPE: if(icmp4==NULL)break; outPrint(DBG_3, "%s() Trying to match ICMPv4 Type", __func__); if( icmp4->getType()==fspec->value[0] ){ outPrint(DBG_3, "[Match] ICMPv4 Type=%02x", icmp4->getType()); current_score += 1 * FACTOR_ICMP_TYPE; } break; case PSPEC_ICMP_CODE: if(icmp4==NULL)break; outPrint(DBG_3, "%s() Trying to match ICMPv4 Code", __func__); if( icmp4->getCode()==fspec->value[0] ){ outPrint(DBG_3, "[Match] ICMPv4 Code=%02x", icmp4->getCode()); current_score += 1 * FACTOR_ICMP_CODE * ((icmp4->getCode()==0) ? ZERO_PENALTY : 1); } break; case PSPEC_UDP_SPORT: if(udp==NULL)break; outPrint(DBG_3, "%s() Trying to match UDP Source Port", __func__); if( udp->getSourcePort()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] UDP Src=%u", udp->getSourcePort()); current_score += 2 * FACTOR_UDP_SPORT; } break; case PSPEC_UDP_DPORT: if(udp==NULL)break; outPrint(DBG_3, "%s() Trying to match UDP Destination Port", __func__); if( udp->getDestinationPort()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] UDP Dst=%u", udp->getDestinationPort()); current_score += 2 * FACTOR_UDP_DPORT; } break; case PSPEC_UDP_LEN: if(udp==NULL)break; outPrint(DBG_3, "%s() Trying to match UDP Length", __func__); if( udp->getTotalLength()==ntohs( *((u16 *)fspec->value) ) ){ outPrint(DBG_3, "[Match] UDP Len=%u", udp->getTotalLength()); current_score += 2 * FACTOR_UDP_LEN * ((udp->getTotalLength()==8) ? ZERO_PENALTY : 1); } break; case PSPEC_PAYLOAD_MAGIC: if(payload==NULL)break; outPrint(DBG_3, "%s() Trying to match Payload Magic value", __func__); buff=payload->getBinaryBuffer(&bufflen); if(buff==NULL || bufflen<=0 || fspec->len>bufflen) break; if( memcmp(buff, fspec->value, fspec->len)==0 ){ outPrint(DBG_3|NO_NEWLINE, "[Match] Payload magic=0x"); for(unsigned int i=0; ilen; i++) outPrint(DBG_3|NO_NEWLINE,"%02x", fspec->value[i]); outPrint(DBG_3, ";"); /* The payload magic may affect the score only between * zero and 4 bytes. This is done to prevent long * common strings like "GET / HTTP/1.1\r\n" * increasing the score a lot and cause problems for * the matching logic. */ current_score+= MIN(4, fspec->len)*FACTOR_PAYLOAD_MAGIC; } break; default: outError(QT_2, "Bogus field specifier found in client #%d context. Please report a bug", ctx->getIdentifier()); break; } } /* End of field specifiers loop */ outPrint(DBG_3, "%s() current_score=%.02f candidate_score=%.02f", __func__, current_score, candidate_score); if( (current_score>0) && (current_score>=candidate_score)){ candidate_score=current_score; candidate=ctx->getIdentifier(); outPrint(DBG_3, "%s() Found better candidate (client #%d; score=%.02f)", __func__, candidate, candidate_score); } } } /* End of connected clients loop */ if( tcp!=NULL ) minimum_score=MIN_ACCEPTABLE_SCORE_TCP; else if (udp!=NULL) minimum_score=MIN_ACCEPTABLE_SCORE_UDP; else if(icmp4!=NULL) minimum_score=MIN_ACCEPTABLE_SCORE_ICMP; else minimum_score=10000; /* Check if we managed to match packet and client */ if (candidate>=0 && candidate_score>=minimum_score){ outPrint(DBG_2, "%s() Packet matched successfully with client #%d", __func__, candidate); return candidate; }else{ if(candidate<0) outPrint(DBG_2, "%s() Couldn't match packet with any client.", __func__); else outPrint(DBG_2, "%s() Found matching client but score is too low. Discarded.", __func__); return CLIENT_NOT_FOUND; } return CLIENT_NOT_FOUND; } /* End of nep_match_ipv4() */ clientid_t EchoServer::nep_match_packet(const u8 *pkt, size_t pktlen){ outPrint(DBG_4, "%s(%p, %lu)", __func__, pkt, (long unsigned)pktlen); int iplen=0, ip6len=0, tcplen=0, udplen=0; bool payload_included=false; IPv4Header ip4; IPv6Header ip6; TCPHeader tcp; UDPHeader udp; ICMPv4Header icmp4; RawData payload; if(this->client_id_count<0){ outPrint(DBG_1, "Error trying to match the packet. No clients connected."); return CLIENT_NOT_FOUND; }else if(pktlennep_match_headers(&ip4, NULL, NULL, NULL, &icmp4, NULL); break; case 6: // TCP if( tcp.storeRecvData(pkt+iplen, pktlen-iplen)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (tcplen=tcp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (iplen+tcplen) ){ if( payload.storeRecvData(pkt+iplen+tcplen, pktlen-iplen-tcplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(&ip4, NULL, &tcp, NULL, NULL, &payload); else return this->nep_match_headers(&ip4, NULL, &tcp, NULL, NULL, NULL); } } break; case 17: // UDP if( udp.storeRecvData(pkt+iplen, pktlen-iplen)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (udplen=udp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (iplen+udplen) ){ if( payload.storeRecvData(pkt+iplen+udplen, pktlen-iplen-udplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(&ip4, NULL, NULL, &udp, NULL, &payload); else return this->nep_match_headers(&ip4, NULL, NULL, &udp, NULL, NULL); } } break; case 41: /* IPv6 encapsulated in the IPv4 datagram! */ if( ip6.storeRecvData(pkt+iplen, pktlen-iplen)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (ip6len=ip6.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ switch( ip6.getNextHeader() ){ case 58: // ICMPv6 outPrint(DBG_4, "Encapsulated IPv4{ IPv6{ ICMPv6 } } received. Not supported."); return CLIENT_NOT_FOUND; break; case 6: // TCP if( tcp.storeRecvData(pkt+ip6len+iplen, pktlen-ip6len-iplen)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (tcplen=tcp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (ip6len+iplen+tcplen) ){ if( payload.storeRecvData(pkt+ip6len+iplen+tcplen, pktlen-ip6len-iplen-tcplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(&ip4, &ip6, &tcp, NULL, NULL, &payload); else return this->nep_match_headers(&ip4, &ip6, &tcp, NULL, NULL, NULL); } } break; case 17: // UDP if( udp.storeRecvData(pkt+ip6len+iplen, pktlen-ip6len-iplen)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (udplen=udp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (ip6len+iplen+udplen) ){ if( payload.storeRecvData(pkt+ip6len+iplen+udplen, pktlen-ip6len-iplen-udplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(&ip4, &ip6, NULL, &udp, NULL, &payload); else return this->nep_match_headers(&ip4, &ip6, NULL, &udp, NULL, NULL); } } break; default: return CLIENT_NOT_FOUND; break; } } } break; default: return CLIENT_NOT_FOUND; break; } } }else if(ip4.getVersion()==0x06){ outPrint(DBG_2, "Recv packet is IPv6. Trying to find a matching client."); if (ip6.storeRecvData(pkt, pktlen)==OP_FAILURE) return CLIENT_NOT_FOUND; if( (ip6len=ip6.validate())==OP_FAILURE ) return CLIENT_NOT_FOUND; switch( ip6.getNextHeader() ){ case 58: // ICMPv6 outPrint(DBG_4, "Received ICMPv6 packet. Not yet supported."); return CLIENT_NOT_FOUND; break; case 6: // TCP if( tcp.storeRecvData(pkt+ip6len, pktlen-ip6len)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (tcplen=tcp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (ip6len+tcplen) ){ if( payload.storeRecvData(pkt+ip6len+tcplen, pktlen-ip6len-tcplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(NULL, &ip6, &tcp, NULL, NULL, &payload); else return this->nep_match_headers(NULL, &ip6, &tcp, NULL, NULL, NULL); } } break; case 17: // UDP if( udp.storeRecvData(pkt+ip6len, pktlen-ip6len)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (udplen=udp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (ip6len+udplen) ){ if( payload.storeRecvData(pkt+ip6len+udplen, pktlen-ip6len-udplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(NULL, &ip6, NULL, &udp, NULL, &payload); else return this->nep_match_headers(NULL, &ip6, NULL, &udp, NULL, NULL); } } break; case 4: /* IPv4 encapsulated in the IPv6 datagram */ if( ip4.storeRecvData(pkt+ip6len, pktlen-ip6len)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (iplen=ip4.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ switch( ip4.getNextProto() ){ case 1: // ICMP if( icmp4.storeRecvData(pkt+ip6len+iplen, pktlen-ip6len-iplen)==OP_FAILURE ) return CLIENT_NOT_FOUND; else return this->nep_match_headers(&ip4, &ip6, NULL, NULL, &icmp4, NULL); break; case 6: // TCP if( tcp.storeRecvData(pkt+ip6len+iplen, pktlen-ip6len-iplen)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (tcplen=tcp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (ip6len+iplen+tcplen) ){ if( payload.storeRecvData(pkt+ip6len+iplen+tcplen, pktlen-ip6len-iplen-tcplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(&ip4, &ip6, &tcp, NULL, NULL, &payload); else return this->nep_match_headers(&ip4, &ip6, &tcp, NULL, NULL, NULL); } } break; case 17: // UDP if( udp.storeRecvData(pkt+ip6len+iplen, pktlen-ip6len-iplen)==OP_FAILURE ){ return CLIENT_NOT_FOUND; }else{ if( (udplen=udp.validate())==OP_FAILURE){ return CLIENT_NOT_FOUND; }else{ if( (int)pktlen > (ip6len+iplen+udplen) ){ if( payload.storeRecvData(pkt+ip6len+iplen+udplen, pktlen-ip6len-iplen-udplen)!=OP_FAILURE) payload_included=true; } if(payload_included) return this->nep_match_headers(&ip4, &ip6, NULL, &udp, NULL, &payload); else return this->nep_match_headers(&ip4, &ip6, NULL, &udp, NULL, NULL); } } break; default: return CLIENT_NOT_FOUND; break; } } } break; default: return CLIENT_NOT_FOUND; break; } }else{ outPrint(DBG_2, "Received packet is not IP: Discarded."); return CLIENT_NOT_FOUND; } return CLIENT_NOT_FOUND; } /* End of nep_match_packet() */ int EchoServer::nep_capture_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); clientid_t clnt=CLIENT_NOT_FOUND; const unsigned char *packet=NULL; const unsigned char *link=NULL; nsock_iod nsi = nse_iod(nse); struct timeval pcaptime; nsock_iod clnt_iod=NULL; NEPContext *ctx=NULL; EchoHeader pkt_out; size_t linklen=0; size_t packetlen=0; handler_arg_t arg; arg.me=this; arg.param=NULL; /* If there are connected clients, schedule another packet capture event */ if(this->client_ctx.size()>0){ nsock_pcap_read_packet(nsp, nsi, capture_handler, NSOCK_INFINITE, &arg); outPrint(DBG_3, "Scheduled next capture event"); } /* Get the actual captured packet */ nse_readpcap(nse, &link, &linklen, &packet, &packetlen, NULL, &pcaptime); outPrint(DBG_3, "Captured %lu bytes", (unsigned long)packetlen); /* Update Rx stats */ o.stats.addRecvPacket(packetlen); /* Try to match received packet with a connected client. */ if( (clnt=this->nep_match_packet(packet, packetlen)) == CLIENT_NOT_FOUND ){ outPrint(DBG_3, "Couldn't match captured packet with a client"); return OP_FAILURE; }else{ outPrint(DBG_4, "Captured packet belongs to client #%d", clnt); } /* Fetch client context */ if( (ctx=this->getClientContext(clnt)) == NULL ){ outPrint(DBG_2, "Error: no context found for client #%d", clnt); return OP_FAILURE; } /* Lookup client's IOD */ if( (clnt_iod=ctx->getNsockIOD()) == NULL ){ outPrint(DBG_2, "Error: no IOD found for client #%d", clnt); return OP_FAILURE; } if( ctx->ready() ){ this->generate_echo(&pkt_out, packet, packetlen, ctx); nsock_write(nsp, clnt_iod, echo_handler, NSOCK_INFINITE, NULL, (const char *)pkt_out.getBinaryBuffer(), pkt_out.getLen()); o.stats.addEchoedPacket(packetlen); } return OP_SUCCESS; } /* End of nep_capture_handler() */ int EchoServer::nep_echo_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); enum nse_status status=nse_status(nse); if (status!=NSE_STATUS_SUCCESS){ outPrint(DBG_1, "Couldn't send NEP_ECHO. Terminating client session\n"); this->nep_session_ended_handler(nsp, nse, param); }else{ outPrint(DBG_1, "SENT: NEP_ECHO"); } return OP_SUCCESS; } /* End of nep_echo_handler() */ int EchoServer::nep_hs_server_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); nsock_iod nsi = nse_iod(nse); NEPContext *ctx=NULL; enum nse_status status=nse_status(nse); if (status!=NSE_STATUS_SUCCESS){ outPrint(DBG_1, "Couldn't send NEP_HANDSHAKE_SERVER. Terminating client session\n"); this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; } /* Lookup client context and schedule a read operation to receive a * NEP_HANDSHAKE_CLIENT message */ if( (ctx=this->getClientContext(nsi))!=NULL ){ ctx->setState(STATE_HS_SERVER_SENT); outPrint(DBG_1, "SENT: NEP_HANDSHAKE_SERVER to %s", IPtoa(ctx->getAddress())); nsock_readbytes(nsp, nsi, hs_client_handler, NSOCK_INFINITE, NULL, NEP_HANDSHAKE_CLIENT_LEN); } return OP_SUCCESS; } /* End of nep_hs_server_handler() */ int EchoServer::nep_hs_client_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); nsock_iod nsi = nse_iod(nse); NEPContext *ctx=NULL; EchoHeader pkt_out; u8 *inbuff=NULL; int inlen=0; enum nse_status status=nse_status(nse); if (status!=NSE_STATUS_SUCCESS){ outPrint(DBG_1, "Failed to receive NEP_HANDSHAKE_CLIENT. Terminating client session"); this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; }else{ outPrint(DBG_1, "RCVD: NEP_HANDSHAKE_CLIENT"); } /* Lookup client context */ if( (ctx=this->getClientContext(nsi))==NULL ){ this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; } /* Ask nsock to provide received data */ if( (inbuff=(u8 *)nse_readbuf(nse, &inlen))==NULL ){ this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; } /* Validate received NEP_HANDSHAKE_CLIENT */ if( this->parse_hs_client(inbuff, inlen, ctx)!=OP_SUCCESS ){ this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; } ctx->setState(STATE_HS_FINAL_SENT); /* Craft a NEP_HANDSHAKE_FINAL message and send it to the client */ if( this->generate_hs_final(&pkt_out, ctx)!=OP_SUCCESS ){ this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; } nsock_write(nsp, nsi, hs_final_handler, NSOCK_INFINITE, NULL, (const char *)pkt_out.getBinaryBuffer(), pkt_out.getLen()); return OP_SUCCESS; } /* End of nep_hs_client_handler() */ int EchoServer::nep_hs_final_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); nsock_iod nsi = nse_iod(nse); outPrint(DBG_1, "SENT: NEP_HANDSHAKE_FINAL"); /* Receive NEP_PACKETSPEC */ nsock_readbytes(nsp, nsi, packetspec_handler, NSOCK_INFINITE, NULL, NEP_PACKETSPEC_LEN); return OP_SUCCESS; } /* End of nep_hs_final_handler() */ int EchoServer::nep_packetspec_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); nsock_iod nsi = nse_iod(nse); EchoHeader pkt_in; EchoHeader pkt_out; NEPContext *ctx=NULL; u8 *recvbuff=NULL; int recvbytes=0; enum nse_status status=nse_status(nse); if (status!=NSE_STATUS_SUCCESS){ outPrint(DBG_1, "Failed to receive NEP_PACKET_SPEC message. Terminating client session\n"); this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; }else{ outPrint(DBG_1, "RCVD: NEP_PACKETSPEC"); } /* Lookup client context */ if( (ctx=this->getClientContext(nsi))==NULL ){ this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; } /* Ask nsock to provide received data */ if( (recvbuff=(u8 *)nse_readbuf(nse, &recvbytes))==NULL ){ this->nep_session_ended_handler(nsp, nse, param); return OP_FAILURE; } /* Validate received NEP_PACKET_SPEC message */ if( this->parse_packet_spec(recvbuff, recvbytes, ctx)!=OP_SUCCESS ){ this->nep_session_ended_handler(nsp, nse, param); outPrint(VB_1, "[%lu] Couldn't establish NEP session with client #%d (%s:%d).", (unsigned long)time(NULL), ctx->getIdentifier(), IPtoa(ctx->getAddress()), sockaddr2port(ctx->getAddress())); return OP_FAILURE; } ctx->setState(STATE_READY_SENT); outPrint(VB_1, "[%lu] NEP handshake with client #%d (%s:%d) was performed successfully", (unsigned long)time(NULL), ctx->getIdentifier(), IPtoa(ctx->getAddress()), sockaddr2port(ctx->getAddress())); /* Craft response and send it */ this->generate_ready(&pkt_out, ctx); nsock_write(nsp, nsi, ready_handler, NSOCK_INFINITE, NULL, (const char *)pkt_out.getBinaryBuffer(), pkt_out.getLen()); /* From this point, the client is not supposed to send anything to the server * through the side channel. However, we now schedule a read operation so * we detect when the client disconnects (because Nsock will tell us). */ nsock_readbytes(nsp, nsi, session_ended_handler, NSOCK_INFINITE, NULL, 65535); /* At this point, we consider the NEP session fully established and therefore * we update the count of served clients */ o.stats.addEchoClientServed(); return OP_SUCCESS; } /* End of nep_packetspec_handler() */ int EchoServer::nep_ready_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); outPrint(DBG_1, "SENT: NEP_READY"); return OP_SUCCESS; } /* End of nep_ready_handler() */ int EchoServer::nep_session_ended_handler(nsock_pool nsp, nsock_event nse, void *param){ outPrint(DBG_4, "%s()", __func__); nsock_iod nsi = nse_iod(nse); clientid_t clnt; NEPContext *ctx=NULL; /* Lookup client context */ if( (ctx=this->getClientContext(nsi))!=NULL ){ outPrint(VB_0, "[%lu] Client #%d (%s:%d) disconnected", (unsigned long)time(NULL), ctx->getIdentifier(), IPtoa(ctx->getAddress()), sockaddr2port(ctx->getAddress())); clnt=ctx->getIdentifier(); if(this->destroyClientContext(clnt)!=OP_SUCCESS) outPrint(DBG_2, "Client #%d disconnected but no context found. This may be a bug.", clnt); else outPrint(DBG_2, "Deleted client #%d context.", clnt); } nsi_delete(nsi, NSOCK_PENDING_SILENT); /* Exit the server if --once has been set */ if(o.once()){ o.displayStatistics(); o.displayNpingDoneMsg(); o.cleanup(); exit(EXIT_SUCCESS); } return OP_SUCCESS; } /* End of nep_session_ended_handler() */ /** Processes and validates a received NEP_HANDSHAKE_CLIENT message. On success * it returns OP_SUCCESS. OP_FAILURE is returned in case the received packet * is not valid. */ int EchoServer::parse_hs_client(u8 *pkt, size_t pktlen, NEPContext *ctx){ outPrint(DBG_4, "%s()", __func__); u8 *next_iv=NULL; EchoHeader h; if(pkt==NULL || ctx==NULL){ outPrint(DBG_1,"%s(): NULL parameter supplied.", __func__ ); return OP_FAILURE; } if(pktlen!=NEP_HANDSHAKE_CLIENT_LEN){ outPrint(DBG_1,"%s(): Unexpected length supplied.", __func__ ); return OP_FAILURE; } h.storeRecvData(pkt, pktlen); /* Validate version number */ if( h.getVersion() != ECHO_CURRENT_PROTO_VER ){ outPrint(DBG_1, "Expected NEP version %02x but message used %02x", ECHO_CURRENT_PROTO_VER, h.getVersion() ); return OP_FAILURE; } /* Ensure the expected message type was received */ if(h.getMessageType()!=TYPE_NEP_HANDSHAKE_CLIENT){ outPrint(DBG_1, "Expected NEP_HANDSHAKE_CLIENT but received %02X", h.getMessageType() ); return OP_FAILURE; } /* Ensure the received timestamp falls into the allowed time window */ //if( h.verifyTimestamp()!=OP_SUCCESS ){ // outPrint(DBG_1, "NEP_HANDSHAKE_CLIENT timestamp is too old", h.getMessageType() ); // return OP_FAILURE; //} /* Ensure message length is correct */ if( h.getTotalLength()!=(NEP_HANDSHAKE_CLIENT_LEN/4)){ outPrint(DBG_1, "Received NEP_HANDSHAKE_CLIENT specifies an incorrect length (%u)", h.getTotalLength()*4 ); return OP_FAILURE; } /* Ensure the client echoed the nonce we sent in our NEP_HANDSHAKE_SERVER */ if( memcmp(h.getServerNonce(), ctx->getServerNonce(), NONCE_LEN)!=0 ){ outPrint(DBG_1, "Echoed nonce in NEP_HANDSHAKE_CLIENT message does not match client generate nonce"); return OP_FAILURE; } /* Store the received nonce */ ctx->setClientNonce(h.getClientNonce()); /* Store client's sequence number */ ctx->setLastClientSequence( h.getSequenceNumber() ); /* Generate all session keys */ ctx->generateCipherKeyC2S(); ctx->generateCipherKeyS2C(); ctx->generateMacKeyC2S(); ctx->generateMacKeyS2C(); outPrint(DBG_3,"Session Key MAC_C2S:"); print_hexdump(DBG_3,ctx->getMacKeyC2S(), MAC_KEY_LEN); outPrint(DBG_3,"Session Key MAC_S2C:"); print_hexdump(DBG_3,ctx->getMacKeyS2C(), MAC_KEY_LEN); outPrint(DBG_3,"Session Key CIPHER_C2S:"); print_hexdump(DBG_3,ctx->getCipherKeyC2S(), MAC_KEY_LEN); outPrint(DBG_3,"Session Key CIPHER_S2C:"); print_hexdump(DBG_3,ctx->getCipherKeyS2C(), MAC_KEY_LEN); /* Decrypt the encrypted part of the message before validating the MAC */ if((next_iv=h.decrypt(ctx->getCipherKeyC2S(), CIPHER_KEY_LEN, ctx->getClientNonce(), TYPE_NEP_HANDSHAKE_CLIENT))==NULL){ outPrint(DBG_1, "Failed to decrypt NEP_HANDSHAKE_CLIENT data." ); return OP_FAILURE; } ctx->setNextDecryptionIV(next_iv); /* Check the authenticity of the received message */ if( h.verifyMessageAuthenticationCode( ctx->getMacKeyC2S(), MAC_KEY_LEN)!=OP_SUCCESS ){ outPrint(DBG_1, "NEP_HANDSHAKE_CLIENT authentication failed" ); return OP_FAILURE; } return OP_SUCCESS; } /* End of parse_hs_client() */ /** Processes and validates a received NEP_PACKET_SPEC message. On success * it returns OP_SUCCESS. OP_FAILURE is returned in case the received packet * is not valid. */ int EchoServer::parse_packet_spec(u8 *pkt, size_t pktlen, NEPContext *ctx){ outPrint(DBG_4, "%s()", __func__); EchoHeader h; int recvspecs=0; bool id_received=false; u8 field=0; size_t len=0; u8 *next_iv=NULL; u8 specbuff[PACKETSPEC_FIELD_LEN]; if(pkt==NULL){ outPrint(DBG_1,"%s(): NULL parameter supplied.", __func__ ); return OP_FAILURE; } if(pktlen!=NEP_PACKETSPEC_LEN){ outPrint(DBG_1,"%s(): Unexpected length supplied.", __func__ ); return OP_FAILURE; } h.storeRecvData(pkt, pktlen); /* Decrypt message */ if((next_iv=h.decrypt(ctx->getCipherKeyC2S(), CIPHER_KEY_LEN, ctx->getNextDecryptionIV(), TYPE_NEP_PACKET_SPEC))==NULL){ outPrint(DBG_1, "Failed to decrypt NEP_PACKET_SPEC data." ); return OP_FAILURE; } ctx->setNextDecryptionIV(next_iv); /* Validate version number */ if( h.getVersion() != ECHO_CURRENT_PROTO_VER ){ outPrint(DBG_1, "Expected NEP version %02x but message used %02x", ECHO_CURRENT_PROTO_VER, h.getVersion() ); return OP_FAILURE; } /* Ensure the expected message type was received */ if(h.getMessageType()!=TYPE_NEP_PACKET_SPEC){ outPrint(DBG_1, "Expected NEP_PACKET_SPEC but received %02X", h.getMessageType() ); return OP_FAILURE; } /* Ensure the received timestamp falls into the allowed time window */ //if( h.verifyTimestamp()!=OP_SUCCESS ){ // outPrint(DBG_1, "NEP_PACKET_SPEC timestamp is too old", h.getMessageType() ); // return OP_FAILURE; //} /* Ensure message length is correct */ if( h.getTotalLength()!=(NEP_PACKETSPEC_LEN/4)){ outPrint(DBG_1, "Received NEP_PACKET_SPEC specifies an incorrect length (%u)", h.getTotalLength()*4 ); return OP_FAILURE; } /* Ensure the received sequence number is the previous+1 */ if( h.getSequenceNumber()!=(ctx->getLastClientSequence()+1)){ outPrint(DBG_1, "Expected sequence number %d but received %d", ctx->getLastClientSequence()+1, h.getSequenceNumber() ); return OP_FAILURE; }else{ /* Increment next expected sequence number*/ ctx->getNextClientSequence(); } /* Check the authenticity of the received message */ if( h.verifyMessageAuthenticationCode( ctx->getMacKeyC2S(), MAC_KEY_LEN)!=OP_SUCCESS ){ outPrint(DBG_1, "NEP_PACKET_SPEC authentication failed" ); return OP_FAILURE; } /* Now that we have verified the authenticity of the message, let's process * the field specifiers */ while(1){ if( h.getNextFieldSpec(&field, specbuff, &len)==OP_FAILURE ){ break; }else{ /* Ensure the field spec is unique. Malicious users could try to supply * the same spec more than once in order to get higher packet scores. */ if( ctx->isDuplicateFieldSpec(field) ){ outPrint(DBG_1, "Detected duplicate field specs in NEP_PACKET_SPEC message" ); return OP_FAILURE; }else{ ctx->addClientFieldSpec(field, len, specbuff); recvspecs++; } /* Set a flag to indicate that mandatory IPv4 ID or IPv6 Flow has been * supplied by the client */ if(h.getIPVersion()==0x04 && field==PSPEC_IPv4_ID) id_received=true; else if(h.getIPVersion()==0x06 && field==PSPEC_IPv6_FLOW) id_received=true; outPrint(DBG_3|NO_NEWLINE,"RCVD FieldSpec: Type=%02X Len=%02x Data=0x", field, (u8)len); for(unsigned int i=0; i=4){ outPrint(VB_2, "[%lu] Good packet specification received from client #%d (Specs=%d,IP=%d,Proto=%d,Cnt=%d)", (unsigned long)time(NULL), ctx->getIdentifier(), recvspecs, h.getIPVersion(), h.getProtocol(), h.getPacketCount() ); return OP_SUCCESS; }else{ return OP_FAILURE; } } /* End of parse_packet_spec() */ /** Generates a NEP_HANDSHAKE_SERVER message. On success it returns OP_SUCCESS. * OP_FAILURE is returned in case of error. * @warning the caller must ensure that the supplied context object * already contains an initial sequence number and a server nonce. */ int EchoServer::generate_hs_server(EchoHeader *h, NEPContext *ctx){ outPrint(DBG_4, "%s()", __func__); if(h==NULL || ctx==NULL) return OP_FAILURE; /* Craft NEP_HANDSHAKE_SERVER message */ h->setMessageType(TYPE_NEP_HANDSHAKE_SERVER); h->setSequenceNumber( ctx->getLastServerSequence() ); h->setTimestamp(); h->setServerNonce( ctx->getServerNonce() ); h->setTotalLength(); h->setMessageAuthenticationCode( ctx->getMacKeyS2C(), MAC_KEY_LEN); return OP_SUCCESS; } /* End of generate_hs_server() */ /** Generates a NEP_HANDSHAKE_FINAL message. On success it returns OP_SUCCESS. * OP_FAILURE is returned in case of error. */ int EchoServer::generate_hs_final(EchoHeader *h, NEPContext *ctx){ outPrint(DBG_4, "%s()", __func__); struct sockaddr_storage ss; u8 *next_iv=NULL; if(h==NULL || ctx==NULL) return OP_FAILURE; /* Craft NEP_HANDSHAKE_CLIENT message */ h->setMessageType(TYPE_NEP_HANDSHAKE_FINAL); h->setSequenceNumber(ctx->getNextServerSequence() ); h->setTimestamp(); h->setClientNonce( ctx->getClientNonce() ); ss=ctx->getAddress(); if(ss.ss_family==AF_INET6){ struct sockaddr_in6 *s6=(struct sockaddr_in6 *)&ss; h->setPartnerAddress(s6->sin6_addr); }else{ struct sockaddr_in *s4=(struct sockaddr_in *)&ss; h->setPartnerAddress(s4->sin_addr); } h->setTotalLength(); h->setMessageAuthenticationCode( ctx->getMacKeyS2C(), MAC_KEY_LEN); /* Encrypt message */ if( (next_iv=h->encrypt(ctx->getCipherKeyS2C(), CIPHER_KEY_LEN, ctx->getServerNonce()))==NULL ) return OP_FAILURE; ctx->setNextEncryptionIV(next_iv); return OP_SUCCESS; } /* End of generate_hs_final() */ /** Generates a NEP_READY message. On success it returns OP_SUCCESS. * OP_FAILURE is returned in case of error. */ int EchoServer::generate_ready(EchoHeader *h, NEPContext *ctx){ outPrint(DBG_4, "%s()", __func__); u8 *next_iv=NULL; if(h==NULL || ctx==NULL) return OP_FAILURE; /* Craft NEP_READY message */ h->setMessageType(TYPE_NEP_READY); h->setSequenceNumber( ctx->getNextServerSequence() ); h->setTimestamp(); h->setTotalLength(); h->setMessageAuthenticationCode(ctx->getMacKeyS2C(), MAC_KEY_LEN); /* Encrypt message */ if( (next_iv=h->encrypt(ctx->getCipherKeyS2C(), CIPHER_KEY_LEN, ctx->getNextEncryptionIV()))==NULL ) return OP_FAILURE; ctx->setNextEncryptionIV(next_iv); return OP_SUCCESS; } /* End of generate_ready() */ /** Generates a NEP_ECHO message. On success it returns OP_SUCCESS. * OP_FAILURE is returned in case of error. */ int EchoServer::generate_echo(EchoHeader *h, const u8 *pkt, size_t pktlen, NEPContext *ctx){ outPrint(DBG_4, "%s()", __func__); u8 *next_iv=NULL; if(h==NULL || ctx==NULL || pkt==NULL || pktlen==0) return OP_FAILURE; /* Craft NEP_ECHO message */ h->setMessageType(TYPE_NEP_ECHO); h->setSequenceNumber( ctx->getNextServerSequence() ); h->setTimestamp(); h->setDLT(DLT_NODATALINKHEADERINCLUDED); /* If allowed, echo the whole packet, including any application layer data */ if( o.echoPayload() ){ h->setEchoedPacket(pkt, pktlen); /* Otherwise, find if the packet contains application layer data and erase it */ }else{ /* Determine where the application data starts */ int offset=PacketParser::payload_offset(pkt, pktlen, false); /* If the packet does not have application data, don't touch it */ if(offset==0){ outPrint(DBG_3, "No payload found. Echoing the whole packet\n"); h->setEchoedPacket(pkt, pktlen); /* If we found application data, zero it */ }else{ outPrint(DBG_3, "Erasing %d payload bytes\n", (int)pktlen-offset); /* Allocate a new buffer, big enough to hold the packet */ u8 *new_pkt=(u8 *)safe_zalloc(pktlen); /* Copy the initial header, and leave the rest as 0x00 bytes */ if(offset>0 && offset<(int)pktlen){ memcpy(new_pkt, pkt, offset); /* If there was some error trying to find application data, include a * default amount of data */ }else{ memcpy(new_pkt, pkt, MIN(pktlen, PAYLOAD_ECHO_BYTES_IN_DOUBT)); } h->setEchoedPacket(new_pkt, pktlen); free(new_pkt); } } h->setTotalLength(); h->setMessageAuthenticationCode(ctx->getMacKeyS2C(), MAC_KEY_LEN); if( (next_iv=h->encrypt(ctx->getCipherKeyS2C(), CIPHER_KEY_LEN, ctx->getNextEncryptionIV()))==NULL ) return OP_FAILURE; ctx->setNextEncryptionIV(next_iv); return OP_SUCCESS; } /* End of generate_echo() */ /** This is the server's main method. It sets up nsock and pcap, waits for * client connections and handles all the events of the client sessions. */ int EchoServer::start() { outPrint(DBG_4, "%s()", __func__); nsock_pool nsp; /**< Nsock pool */ enum nsock_loopstatus loopret; /**< Stores nsock_loop returned status */ nsock_iod client_nsi; /**< Stores connected client IOD */ nsock_iod pcap_nsi; /**< Stores Pcap IOD */ char pcapdev[128]; /**< Device name passed to pcap_open_live */ char *auxpnt=NULL; /**< Aux str pointer */ struct timeval now; /**< For timestamps */ struct sockaddr_storage ss; /**< New client socket address */ socklen_t sslen=sizeof(ss); /**< New client socket address len */ int listen_sd=-1; /**< Socket descriptor for listening */ int client_sd=-1; /**< Socket descriptor for new clients */ clientid_t *idpnt=NULL; /**< For new client assigned identifiers */ NEPContext ctx; /**< Context for the new client */ EchoHeader h; /* Create a new nsock pool */ if ((nsp = nsp_new(NULL)) == NULL) outFatal(QT_3, "Failed to create new pool. QUITTING.\n"); /* Set nsock trace level */ gettimeofday(&now, NULL); if( o.getDebugging() == DBG_5 ) nsock_set_loglevel(nsp, NSOCK_LOG_INFO); else if( o.getDebugging() > DBG_5 ) nsock_set_loglevel(nsp, NSOCK_LOG_DBG_ALL); /* Create new IOD for pcap */ if ((pcap_nsi = nsi_new(nsp, NULL)) == NULL) outFatal(QT_3, "Failed to create new nsock_iod. QUITTING.\n"); /* Open pcap */ outPrint(DBG_2,"Opening pcap device %s", o.getDevice() ); Strncpy(pcapdev, o.getDevice(), sizeof(pcapdev)); if( (auxpnt=nsock_pcap_open(nsp, pcap_nsi, pcapdev, MAX_ECHOED_PACKET_LEN, 1, ProbeMode::getBPFFilterString() )) != NULL ) outFatal(QT_3, "Error opening capture device %s --> %s\n", o.getDevice(), auxpnt); else outPrint(VB_0,"Packet capture will be performed using network interface %s.", o.getDevice()); outPrint(VB_0,"Waiting for connections..."); /* Get a socket suitable for an accept() call */ listen_sd=this->nep_listen_socket(); while(1){ /* If --once is enabled, just allow the first client */ if(o.once()==false || this->client_id_count==-1){ /* Check if we have received a connection*/ unblock_socket(listen_sd); if ((client_sd=accept(listen_sd, (struct sockaddr *)&ss, &sslen)) >= 0){ outPrint(VB_0, "[%lu] Connection received from %s:%d", (unsigned long)time(NULL), IPtoa(&ss), sockaddr2port(&ss)); /* Assign a new client identifier. The ID is bound to the IOD */ if( (idpnt=(clientid_t *)calloc(1, sizeof(clientid_t)))==NULL ){ outError(QT_2, "Not enough memory for new clients."); return OP_FAILURE; } *idpnt=this->getNewClientID(); if( (client_nsi=nsi_new2(nsp, client_sd, idpnt))==NULL ){ outError(QT_2, "Not enough memory for new clients."); return OP_FAILURE; }else{ close(client_sd); /* nsi_new2() dups the socket */ } /* Stop listening if --once is enabled */ if(o.once()==true) close(listen_sd); /* Create a new client context object */ ctx.setIdentifier(*idpnt); ctx.setAddress(ss); ctx.setNsockIOD(client_nsi); ctx.generateServerNonce(); ctx.generateInitialServerSequence(); ctx.generateMacKeyS2CInitial(); outPrint(DBG_3,"Session Key MAC_S2C_INITIAL:"); print_hexdump(DBG_3,ctx.getMacKeyS2C(), MAC_KEY_LEN); /* Craft NEP_HANDSHAKE_SERVER message */ if( this->generate_hs_server(&h, &ctx)!=OP_SUCCESS) return OP_FAILURE; else this->addClientContext(ctx); /* Schedule send operation */ nsock_write(nsp, client_nsi, hs_server_handler, NSOCK_INFINITE, NULL, (const char *)h.getBufferPointer(), h.getLen() ); /* For every client we schedule a packet capture event. */ nsock_pcap_read_packet(nsp, pcap_nsi, capture_handler, NSOCK_INFINITE, NULL); } block_socket(listen_sd); } /* Sleep for a second until we check again for incoming connection requests */ nsock_timer_create(nsp, empty_handler, 1000, NULL); loopret=nsock_loop(nsp, 1000); //If something went wrong in nsock_loop, let's just bail out. if (loopret == NSOCK_LOOP_ERROR) { outError(QT_3, "Unexpected nsock_loop error.\n"); return OP_FAILURE; } } return OP_SUCCESS; } /* End of start() */ /** Performs cleanup functions */ int EchoServer::cleanup(){ // For the moment there is nothing to cleanup return OP_SUCCESS; } /* End of cleanup() */ /******************************************************************************/ /**** HANDLER WRAPPERS ********************************************************/ /******************************************************************************/ /* This handler is a wrapper for the EchoServer::nep_read_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void capture_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_capture_handler(nsp, nse, arg); return; } /* End of capture_handler() */ /* This handler is a wrapper for the EchoServer::nep_echo_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void echo_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_echo_handler(nsp, nse, arg); return; } /* End of echo_handler() */ /* This handler is a wrapper for the EchoServer::nep_hs_server_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void hs_server_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_hs_server_handler(nsp, nse, arg); return; } /* End of hs_server_handler() */ /* This handler is a wrapper for the EchoServer::nep_hs_client_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void hs_client_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_hs_client_handler(nsp, nse, arg); return; } /* End of hs_client_handler() */ /* This handler is a wrapper for the EchoServer::nep_hs_final_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void hs_final_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_hs_final_handler(nsp, nse, arg); return; } /* End of hs_final_handler() */ /* This handler is a wrapper for the EchoServer::nep_packetspec_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void packetspec_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_packetspec_handler(nsp, nse, arg); return; } /* End of packetspec_handler() */ /* This handler is a wrapper for the EchoServer::nep_ready_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void ready_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_ready_handler(nsp, nse, arg); return; } /* End of ready_handler() */ /* This handler is a wrapper for the EchoServer::nep_ready_handler() method. We * need this because C++ does not allow to use class methods as callback * functions for things like signal() or the Nsock lib. */ void session_ended_handler(nsock_pool nsp, nsock_event nse, void *arg){ outPrint(DBG_4, "%s()", __func__); es.nep_session_ended_handler(nsp, nse, arg); return; } /* End of ready_handler() */ /* Void handler that does nothing */ void empty_handler(nsock_pool nsp, nsock_event nse, void *arg){ return; } /* End of capture_handler() */