/* * Copyright (c) 2002 - 2003 * NetGroup, Politecnico di Torino (Italy) * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the Politecnico di Torino nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #ifdef HAVE_CONFIG_H #include #endif /* * \file sockutils.c * * The goal of this file is to provide a common set of primitives for socket * manipulation. * * Although the socket interface defined in the RFC 2553 (and its updates) * is excellent, there are still differences between the behavior of those * routines on UN*X and Windows, and between UN*Xes. * * These calls provide an interface similar to the socket interface, but * that hides the differences between operating systems. It does not * attempt to significantly improve on the socket interface in other * ways. */ #include "ftmacros.h" #include #include /* for the errno variable */ #include /* for the stderr file */ #include /* for malloc() and free() */ #ifdef HAVE_LIMITS_H #include #else #define INT_MAX 2147483647 #endif #include "pcap-int.h" #include "sockutils.h" #include "portability.h" #ifdef _WIN32 /* * Winsock initialization. * * Ask for WinSock 2.2. */ #define WINSOCK_MAJOR_VERSION 2 #define WINSOCK_MINOR_VERSION 2 static int sockcount = 0; /*!< Variable that allows calling the WSAStartup() only one time */ #endif /* Some minor differences between UNIX and Win32 */ #ifdef _WIN32 #define SHUT_WR SD_SEND /* The control code for shutdown() is different in Win32 */ #endif /* Size of the buffer that has to keep error messages */ #define SOCK_ERRBUF_SIZE 1024 /* Constants; used in order to keep strings here */ #define SOCKET_NO_NAME_AVAILABLE "No name available" #define SOCKET_NO_PORT_AVAILABLE "No port available" #define SOCKET_NAME_NULL_DAD "Null address (possibly DAD Phase)" /* * On UN*X, send() and recv() return ssize_t. * * On Windows, send() and recv() return an int. * * Wth MSVC, there *is* no ssize_t. * * With MinGW, there is an ssize_t type; it is either an int (32 bit) * or a long long (64 bit). * * So, on Windows, if we don't have ssize_t defined, define it as an * int, so we can use it, on all platforms, as the type of variables * that hold the return values from send() and recv(). */ #if defined(_WIN32) && !defined(_SSIZE_T_DEFINED) typedef int ssize_t; #endif /**************************************************** * * * Locally defined functions * * * ****************************************************/ static int sock_ismcastaddr(const struct sockaddr *saddr); /**************************************************** * * * Function bodies * * * ****************************************************/ /* * Format an error message given an errno value (UN*X) or a WinSock error * (Windows). */ void sock_fmterror(const char *caller, int errcode, char *errbuf, int errbuflen) { #ifdef _WIN32 int retval; char message[SOCK_ERRBUF_SIZE]; /* We're forcing "ANSI" */ if (errbuf == NULL) return; retval = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_MAX_WIDTH_MASK, NULL, errcode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), message, sizeof(message) / sizeof(TCHAR), NULL); if (retval == 0) { if ((caller) && (*caller)) pcap_snprintf(errbuf, errbuflen, "%sUnable to get the exact error message", caller); else pcap_snprintf(errbuf, errbuflen, "Unable to get the exact error message"); } else { if ((caller) && (*caller)) pcap_snprintf(errbuf, errbuflen, "%s%s (code %d)", caller, message, errcode); else pcap_snprintf(errbuf, errbuflen, "%s (code %d)", message, errcode); } #else char *message; if (errbuf == NULL) return; message = strerror(errcode); if ((caller) && (*caller)) pcap_snprintf(errbuf, errbuflen, "%s%s (code %d)", caller, message, errcode); else pcap_snprintf(errbuf, errbuflen, "%s (code %d)", message, errcode); #endif } /* * \brief It retrieves the error message after an error occurred in the socket interface. * * This function is defined because of the different way errors are returned in UNIX * and Win32. This function provides a consistent way to retrieve the error message * (after a socket error occurred) on all the platforms. * * \param caller: a pointer to a user-allocated string which contains a message that has * to be printed *before* the true error message. It could be, for example, 'this error * comes from the recv() call at line 31'. It may be NULL. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return No return values. The error message is returned in the 'string' parameter. */ void sock_geterror(const char *caller, char *errbuf, int errbuflen) { #ifdef _WIN32 if (errbuf == NULL) return; sock_fmterror(caller, GetLastError(), errbuf, errbuflen); #else if (errbuf == NULL) return; sock_fmterror(caller, errno, errbuf, errbuflen); #endif } /* * \brief It initializes sockets. * * This function is pretty useless on UNIX, since socket initialization is not required. * However it is required on Win32. In UNIX, this function appears to be completely empty. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return '0' if everything is fine, '-1' if some errors occurred. The error message is returned * in the 'errbuf' variable. */ #ifdef _WIN32 int sock_init(char *errbuf, int errbuflen) { if (sockcount == 0) { WSADATA wsaData; /* helper variable needed to initialize Winsock */ if (WSAStartup(MAKEWORD(WINSOCK_MAJOR_VERSION, WINSOCK_MINOR_VERSION), &wsaData) != 0) { if (errbuf) pcap_snprintf(errbuf, errbuflen, "Failed to initialize Winsock\n"); WSACleanup(); return -1; } } sockcount++; #else int sock_init(char *errbuf _U_, int errbuflen _U_) { #endif return 0; } /* * \brief It deallocates sockets. * * This function is pretty useless on UNIX, since socket deallocation is not required. * However it is required on Win32. In UNIX, this function appears to be completely empty. * * \return No error values. */ void sock_cleanup(void) { #ifdef _WIN32 sockcount--; if (sockcount == 0) WSACleanup(); #endif } /* * \brief It checks if the sockaddr variable contains a multicast address. * * \return '0' if the address is multicast, '-1' if it is not. */ static int sock_ismcastaddr(const struct sockaddr *saddr) { if (saddr->sa_family == PF_INET) { struct sockaddr_in *saddr4 = (struct sockaddr_in *) saddr; if (IN_MULTICAST(ntohl(saddr4->sin_addr.s_addr))) return 0; else return -1; } else { struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *) saddr; if (IN6_IS_ADDR_MULTICAST(&saddr6->sin6_addr)) return 0; else return -1; } } /* * \brief It initializes a network connection both from the client and the server side. * * In case of a client socket, this function calls socket() and connect(). * In the meanwhile, it checks for any socket error. * If an error occurs, it writes the error message into 'errbuf'. * * In case of a server socket, the function calls socket(), bind() and listen(). * * This function is usually preceeded by the sock_initaddress(). * * \param addrinfo: pointer to an addrinfo variable which will be used to * open the socket and such. This variable is the one returned by the previous call to * sock_initaddress(). * * \param server: '1' if this is a server socket, '0' otherwise. * * \param nconn: number of the connections that are allowed to wait into the listen() call. * This value has no meanings in case of a client socket. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return the socket that has been opened (that has to be used in the following sockets calls) * if everything is fine, INVALID_SOCKET if some errors occurred. The error message is returned * in the 'errbuf' variable. */ SOCKET sock_open(struct addrinfo *addrinfo, int server, int nconn, char *errbuf, int errbuflen) { SOCKET sock; #if defined(SO_NOSIGPIPE) || defined(IPV6_V6ONLY) || defined(IPV6_BINDV6ONLY) int on = 1; #endif sock = socket(addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol); if (sock == INVALID_SOCKET) { sock_geterror("socket(): ", errbuf, errbuflen); return INVALID_SOCKET; } /* * Disable SIGPIPE, if we have SO_NOSIGPIPE. We don't want to * have to deal with signals if the peer closes the connection, * especially in client programs, which may not even be aware that * they're sending to sockets. */ #ifdef SO_NOSIGPIPE if (setsockopt(sock, SOL_SOCKET, SO_NOSIGPIPE, (char *)&on, sizeof (int)) == -1) { sock_geterror("setsockopt(SO_NOSIGPIPE)", errbuf, errbuflen); closesocket(sock); return INVALID_SOCKET; } #endif /* This is a server socket */ if (server) { #if defined(IPV6_V6ONLY) || defined(IPV6_BINDV6ONLY) /* * Force the use of IPv6-only addresses. * * RFC 3493 indicates that you can support IPv4 on an * IPv6 socket: * * https://tools.ietf.org/html/rfc3493#section-3.7 * * and that this is the default behavior. This means * that if we first create an IPv6 socket bound to the * "any" address, it is, in effect, also bound to the * IPv4 "any" address, so when we create an IPv4 socket * and try to bind it to the IPv4 "any" address, it gets * EADDRINUSE. * * Not all network stacks support IPv4 on IPv6 sockets; * pre-NT 6 Windows stacks don't support it, and the * OpenBSD stack doesn't support it for security reasons * (see the OpenBSD inet6(4) man page). Therefore, we * don't want to rely on this behavior. * * So we try to disable it, using either the IPV6_V6ONLY * option from RFC 3493: * * https://tools.ietf.org/html/rfc3493#section-5.3 * * or the IPV6_BINDV6ONLY option from older UN*Xes. */ #ifndef IPV6_V6ONLY /* For older systems */ #define IPV6_V6ONLY IPV6_BINDV6ONLY #endif /* IPV6_V6ONLY */ if (addrinfo->ai_family == PF_INET6) { if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&on, sizeof (int)) == -1) { if (errbuf) pcap_snprintf(errbuf, errbuflen, "setsockopt(IPV6_V6ONLY)"); closesocket(sock); return INVALID_SOCKET; } } #endif /* defined(IPV6_V6ONLY) || defined(IPV6_BINDV6ONLY) */ /* WARNING: if the address is a mcast one, I should place the proper Win32 code here */ if (bind(sock, addrinfo->ai_addr, (int) addrinfo->ai_addrlen) != 0) { sock_geterror("bind(): ", errbuf, errbuflen); closesocket(sock); return INVALID_SOCKET; } if (addrinfo->ai_socktype == SOCK_STREAM) if (listen(sock, nconn) == -1) { sock_geterror("listen(): ", errbuf, errbuflen); closesocket(sock); return INVALID_SOCKET; } /* server side ended */ return sock; } else /* we're the client */ { struct addrinfo *tempaddrinfo; char *errbufptr; size_t bufspaceleft; tempaddrinfo = addrinfo; errbufptr = errbuf; bufspaceleft = errbuflen; *errbufptr = 0; /* * We have to loop though all the addinfo returned. * For instance, we can have both IPv6 and IPv4 addresses, but the service we're trying * to connect to is unavailable in IPv6, so we have to try in IPv4 as well */ while (tempaddrinfo) { if (connect(sock, tempaddrinfo->ai_addr, (int) tempaddrinfo->ai_addrlen) == -1) { size_t msglen; char TmpBuffer[100]; char SocketErrorMessage[SOCK_ERRBUF_SIZE]; /* * We have to retrieve the error message before any other socket call completes, otherwise * the error message is lost */ sock_geterror(NULL, SocketErrorMessage, sizeof(SocketErrorMessage)); /* Returns the numeric address of the host that triggered the error */ sock_getascii_addrport((struct sockaddr_storage *) tempaddrinfo->ai_addr, TmpBuffer, sizeof(TmpBuffer), NULL, 0, NI_NUMERICHOST, TmpBuffer, sizeof(TmpBuffer)); pcap_snprintf(errbufptr, bufspaceleft, "Is the server properly installed on %s? connect() failed: %s", TmpBuffer, SocketErrorMessage); /* In case more then one 'connect' fails, we manage to keep all the error messages */ msglen = strlen(errbufptr); errbufptr[msglen] = ' '; errbufptr[msglen + 1] = 0; bufspaceleft = bufspaceleft - (msglen + 1); errbufptr += (msglen + 1); tempaddrinfo = tempaddrinfo->ai_next; } else break; } /* * Check how we exit from the previous loop * If tempaddrinfo is equal to NULL, it means that all the connect() failed. */ if (tempaddrinfo == NULL) { closesocket(sock); return INVALID_SOCKET; } else return sock; } } /* * \brief Closes the present (TCP and UDP) socket connection. * * This function sends a shutdown() on the socket in order to disable send() calls * (while recv() ones are still allowed). Then, it closes the socket. * * \param sock: the socket identifier of the connection that has to be closed. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return '0' if everything is fine, '-1' if some errors occurred. The error message is returned * in the 'errbuf' variable. */ int sock_close(SOCKET sock, char *errbuf, int errbuflen) { /* * SHUT_WR: subsequent calls to the send function are disallowed. * For TCP sockets, a FIN will be sent after all data is sent and * acknowledged by the Server. */ if (shutdown(sock, SHUT_WR)) { sock_geterror("shutdown(): ", errbuf, errbuflen); /* close the socket anyway */ closesocket(sock); return -1; } closesocket(sock); return 0; } /* * \brief Checks that the address, port and flags given are valids and it returns an 'addrinfo' structure. * * This function basically calls the getaddrinfo() calls, and it performs a set of sanity checks * to control that everything is fine (e.g. a TCP socket cannot have a mcast address, and such). * If an error occurs, it writes the error message into 'errbuf'. * * \param host: a pointer to a string identifying the host. It can be * a host name, a numeric literal address, or NULL or "" (useful * in case of a server socket which has to bind to all addresses). * * \param port: a pointer to a user-allocated buffer containing the network port to use. * * \param hints: an addrinfo variable (passed by reference) containing the flags needed to create the * addrinfo structure appropriately. * * \param addrinfo: it represents the true returning value. This is a pointer to an addrinfo variable * (passed by reference), which will be allocated by this function and returned back to the caller. * This variable will be used in the next sockets calls. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return '0' if everything is fine, '-1' if some errors occurred. The error message is returned * in the 'errbuf' variable. The addrinfo variable that has to be used in the following sockets calls is * returned into the addrinfo parameter. * * \warning The 'addrinfo' variable has to be deleted by the programmer by calling freeaddrinfo() when * it is no longer needed. * * \warning This function requires the 'hints' variable as parameter. The semantic of this variable is the same * of the one of the corresponding variable used into the standard getaddrinfo() socket function. We suggest * the programmer to look at that function in order to set the 'hints' variable appropriately. */ int sock_initaddress(const char *host, const char *port, struct addrinfo *hints, struct addrinfo **addrinfo, char *errbuf, int errbuflen) { int retval; retval = getaddrinfo(host, port, hints, addrinfo); if (retval != 0) { /* * if the getaddrinfo() fails, you have to use gai_strerror(), instead of using the standard * error routines (errno) in UNIX; Winsock suggests using the GetLastError() instead. */ if (errbuf) { #ifdef _WIN32 sock_geterror("getaddrinfo(): ", errbuf, errbuflen); #else pcap_snprintf(errbuf, errbuflen, "getaddrinfo() %s", gai_strerror(retval)); #endif } return -1; } /* * \warning SOCKET: I should check all the accept() in order to bind to all addresses in case * addrinfo has more han one pointers */ /* * This software only supports PF_INET and PF_INET6. * * XXX - should we just check that at least *one* address is * either PF_INET or PF_INET6, and, when using the list, * ignore all addresses that are neither? (What, no IPX * support? :-)) */ if (((*addrinfo)->ai_family != PF_INET) && ((*addrinfo)->ai_family != PF_INET6)) { if (errbuf) pcap_snprintf(errbuf, errbuflen, "getaddrinfo(): socket type not supported"); freeaddrinfo(*addrinfo); *addrinfo = NULL; return -1; } /* * You can't do multicast (or broadcast) TCP. */ if (((*addrinfo)->ai_socktype == SOCK_STREAM) && (sock_ismcastaddr((*addrinfo)->ai_addr) == 0)) { if (errbuf) pcap_snprintf(errbuf, errbuflen, "getaddrinfo(): multicast addresses are not valid when using TCP streams"); freeaddrinfo(*addrinfo); *addrinfo = NULL; return -1; } return 0; } /* * \brief It sends the amount of data contained into 'buffer' on the given socket. * * This function basically calls the send() socket function and it checks that all * the data specified in 'buffer' (of size 'size') will be sent. If an error occurs, * it writes the error message into 'errbuf'. * In case the socket buffer does not have enough space, it loops until all data * has been sent. * * \param socket: the connected socket currently opened. * * \param buffer: a char pointer to a user-allocated buffer in which data is contained. * * \param size: number of bytes that have to be sent. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return '0' if everything is fine, '-1' if an error other than * "connection reset" or "peer has closed the receive side" occurred, * '-2' if we got one of those errors. * For errors, an error message is returned in the 'errbuf' variable. */ int sock_send(SOCKET sock, const char *buffer, size_t size, char *errbuf, int errbuflen) { int remaining; ssize_t nsent; if (size > INT_MAX) { if (errbuf) { pcap_snprintf(errbuf, errbuflen, "Can't send more than %u bytes with sock_recv", INT_MAX); } return -1; } remaining = (int)size; do { #ifdef MSG_NOSIGNAL /* * Send with MSG_NOSIGNAL, so that we don't get SIGPIPE * on errors on stream-oriented sockets when the other * end breaks the connection. * The EPIPE error is still returned. */ nsent = send(sock, buffer, remaining, MSG_NOSIGNAL); #else nsent = send(sock, buffer, remaining, 0); #endif if (nsent == -1) { /* * If the client closed the connection out from * under us, there's no need to log that as an * error. */ int errcode; #ifdef _WIN32 errcode = GetLastError(); if (errcode == WSAECONNRESET || errcode == WSAECONNABORTED) { /* * WSAECONNABORTED appears to be the error * returned in Winsock when you try to send * on a connection where the peer has closed * the receive side. */ return -2; } sock_fmterror("send(): ", errcode, errbuf, errbuflen); #else errcode = errno; if (errcode == ECONNRESET || errcode == EPIPE) { /* * EPIPE is what's returned on UN*X when * you try to send on a connection when * the peer has closed the receive side. */ return -2; } sock_fmterror("send(): ", errcode, errbuf, errbuflen); #endif return -1; } remaining -= nsent; buffer += nsent; } while (remaining != 0); return 0; } /* * \brief It copies the amount of data contained into 'buffer' into 'tempbuf'. * and it checks for buffer overflows. * * This function basically copies 'size' bytes of data contained into 'buffer' * into 'tempbuf', starting at offset 'offset'. Before that, it checks that the * resulting buffer will not be larger than 'totsize'. Finally, it updates * the 'offset' variable in order to point to the first empty location of the buffer. * * In case the function is called with 'checkonly' equal to 1, it does not copy * the data into the buffer. It only checks for buffer overflows and it updates the * 'offset' variable. This mode can be useful when the buffer already contains the * data (maybe because the producer writes directly into the target buffer), so * only the buffer overflow check has to be made. * In this case, both 'buffer' and 'tempbuf' can be NULL values. * * This function is useful in case the userland application does not know immediately * all the data it has to write into the socket. This function provides a way to create * the "stream" step by step, appending the new data to the old one. Then, when all the * data has been bufferized, the application can call the sock_send() function. * * \param buffer: a char pointer to a user-allocated buffer that keeps the data * that has to be copied. * * \param size: number of bytes that have to be copied. * * \param tempbuf: user-allocated buffer (of size 'totsize') in which data * has to be copied. * * \param offset: an index into 'tempbuf' which keeps the location of its first * empty location. * * \param totsize: total size of the buffer in which data is being copied. * * \param checkonly: '1' if we do not want to copy data into the buffer and we * want just do a buffer ovreflow control, '0' if data has to be copied as well. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return '0' if everything is fine, '-1' if some errors occurred. The error message * is returned in the 'errbuf' variable. When the function returns, 'tempbuf' will * have the new string appended, and 'offset' will keep the length of that buffer. * In case of 'checkonly == 1', data is not copied, but 'offset' is updated in any case. * * \warning This function assumes that the buffer in which data has to be stored is * large 'totbuf' bytes. * * \warning In case of 'checkonly', be carefully to call this function *before* copying * the data into the buffer. Otherwise, the control about the buffer overflow is useless. */ int sock_bufferize(const char *buffer, int size, char *tempbuf, int *offset, int totsize, int checkonly, char *errbuf, int errbuflen) { if ((*offset + size) > totsize) { if (errbuf) pcap_snprintf(errbuf, errbuflen, "Not enough space in the temporary send buffer."); return -1; } if (!checkonly) memcpy(tempbuf + (*offset), buffer, size); (*offset) += size; return 0; } /* * \brief It waits on a connected socket and it manages to receive data. * * This function basically calls the recv() socket function and it checks that no * error occurred. If that happens, it writes the error message into 'errbuf'. * * This function changes its behavior according to the 'receiveall' flag: if we * want to receive exactly 'size' byte, it loops on the recv() until all the requested * data is arrived. Otherwise, it returns the data currently available. * * In case the socket does not have enough data available, it cycles on the recv() * until the requested data (of size 'size') is arrived. * In this case, it blocks until the number of bytes read is equal to 'size'. * * \param sock: the connected socket currently opened. * * \param buffer: a char pointer to a user-allocated buffer in which data has to be stored * * \param size: size of the allocated buffer. WARNING: this indicates the number of bytes * that we are expecting to be read. * * \param flags: * * SOCK_RECEIVALL_XXX: * * if SOCK_RECEIVEALL_NO, return as soon as some data is ready * if SOCK_RECEIVALL_YES, wait until 'size' data has been * received (in case the socket does not have enough data available). * * SOCK_EOF_XXX: * * if SOCK_EOF_ISNT_ERROR, if the first read returns 0, just return 0, * and return an error on any subsequent read that returns 0; * if SOCK_EOF_IS_ERROR, if any read returns 0, return an error. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return the number of bytes read if everything is fine, '-1' if some errors occurred. * The error message is returned in the 'errbuf' variable. */ int sock_recv(SOCKET sock, void *buffer, size_t size, int flags, char *errbuf, int errbuflen) { char *bufp = buffer; int remaining; ssize_t nread; if (size == 0) { SOCK_DEBUG_MESSAGE("I have been requested to read zero bytes"); return 0; } if (size > INT_MAX) { if (errbuf) { pcap_snprintf(errbuf, errbuflen, "Can't read more than %u bytes with sock_recv", INT_MAX); } return -1; } bufp = (char *) buffer; remaining = (int) size; /* * We don't use MSG_WAITALL because it's not supported in * Win32. */ for (;;) { nread = recv(sock, bufp, remaining, 0); if (nread == -1) { #ifndef _WIN32 if (errno == EINTR) return -3; #endif sock_geterror("recv(): ", errbuf, errbuflen); return -1; } if (nread == 0) { if ((flags & SOCK_EOF_IS_ERROR) || (remaining != (int) size)) { /* * Either we've already read some data, * or we're always supposed to return * an error on EOF. */ if (errbuf) { pcap_snprintf(errbuf, errbuflen, "The other host terminated the connection."); } return -1; } else return 0; } /* * Do we want to read the amount requested, or just return * what we got? */ if (!(flags & SOCK_RECEIVEALL_YES)) { /* * Just return what we got. */ return (int) nread; } bufp += nread; remaining -= nread; if (remaining == 0) return (int) size; } } /* * Receives a datagram from a socket. * * Returns the size of the datagram on success or -1 on error. */ int sock_recv_dgram(SOCKET sock, void *buffer, size_t size, char *errbuf, int errbuflen) { ssize_t nread; #ifndef _WIN32 struct msghdr message; struct iovec iov; #endif if (size == 0) { SOCK_DEBUG_MESSAGE("I have been requested to read zero bytes"); return 0; } if (size > INT_MAX) { if (errbuf) { pcap_snprintf(errbuf, errbuflen, "Can't read more than %u bytes with sock_recv_dgram", INT_MAX); } return -1; } /* * This should be a datagram socket, so we should get the * entire datagram in one recv() or recvmsg() call, and * don't need to loop. */ #ifdef _WIN32 nread = recv(sock, buffer, size, 0); if (nread == SOCKET_ERROR) { /* * To quote the MSDN documentation for recv(), * "If the datagram or message is larger than * the buffer specified, the buffer is filled * with the first part of the datagram, and recv * generates the error WSAEMSGSIZE. For unreliable * protocols (for example, UDP) the excess data is * lost..." * * So if the message is bigger than the buffer * supplied to us, the excess data is discarded, * and we'll report an error. */ sock_geterror("recv(): ", errbuf, errbuflen); return -1; } #else /* _WIN32 */ /* * The Single UNIX Specification says that a recv() on * a socket for a message-oriented protocol will discard * the excess data. It does *not* indicate that the * receive will fail with, for example, EMSGSIZE. * * Therefore, we use recvmsg(), which appears to be * the only way to get a "message truncated" indication * when receiving a message for a message-oriented * protocol. */ message.msg_name = NULL; /* we don't care who it's from */ message.msg_namelen = 0; iov.iov_base = buffer; iov.iov_len = size; message.msg_iov = &iov; message.msg_iovlen = 1; #ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL message.msg_control = NULL; /* we don't care about control information */ message.msg_controllen = 0; #endif #ifdef HAVE_STRUCT_MSGHDR_MSG_FLAGS message.msg_flags = 0; #endif nread = recvmsg(sock, &message, 0); if (nread == -1) { if (errno == EINTR) return -3; sock_geterror("recv(): ", errbuf, errbuflen); return -1; } #ifdef HAVE_STRUCT_MSGHDR_MSG_FLAGS /* * XXX - Solaris supports this, but only if you ask for the * X/Open version of recvmsg(); should we use that, or will * that cause other problems? */ if (message.msg_flags & MSG_TRUNC) { /* * Message was bigger than the specified buffer size. * * Report this as an error, as the Microsoft documentation * implies we'd do in a similar case on Windows. */ pcap_snprintf(errbuf, errbuflen, "recv(): Message too long"); return -1; } #endif /* HAVE_STRUCT_MSGHDR_MSG_FLAGS */ #endif /* _WIN32 */ /* * The size we're reading fits in an int, so the return value * will fit in an int. */ return (int)nread; } /* * \brief It discards N bytes that are currently waiting to be read on the current socket. * * This function is useful in case we receive a message we cannot understand (e.g. * wrong version number when receiving a network packet), so that we have to discard all * data before reading a new message. * * This function will read 'size' bytes from the socket and discard them. * It defines an internal buffer in which data will be copied; however, in case * this buffer is not large enough, it will cycle in order to read everything as well. * * \param sock: the connected socket currently opened. * * \param size: number of bytes that have to be discarded. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return '0' if everything is fine, '-1' if some errors occurred. * The error message is returned in the 'errbuf' variable. */ int sock_discard(SOCKET sock, int size, char *errbuf, int errbuflen) { #define TEMP_BUF_SIZE 32768 char buffer[TEMP_BUF_SIZE]; /* network buffer, to be used when the message is discarded */ /* * A static allocation avoids the need of a 'malloc()' each time we want to discard a message * Our feeling is that a buffer if 32KB is enough for most of the application; * in case this is not enough, the "while" loop discards the message by calling the * sockrecv() several times. * We do not want to create a bigger variable because this causes the program to exit on * some platforms (e.g. BSD) */ while (size > TEMP_BUF_SIZE) { if (sock_recv(sock, buffer, TEMP_BUF_SIZE, SOCK_RECEIVEALL_YES, errbuf, errbuflen) == -1) return -1; size -= TEMP_BUF_SIZE; } /* * If there is still data to be discarded * In this case, the data can fit into the temporary buffer */ if (size) { if (sock_recv(sock, buffer, size, SOCK_RECEIVEALL_YES, errbuf, errbuflen) == -1) return -1; } SOCK_DEBUG_MESSAGE("I'm currently discarding data\n"); return 0; } /* * \brief Checks that one host (identified by the sockaddr_storage structure) belongs to an 'allowed list'. * * This function is useful after an accept() call in order to check if the connecting * host is allowed to connect to me. To do that, we have a buffer that keeps the list of the * allowed host; this function checks the sockaddr_storage structure of the connecting host * against this host list, and it returns '0' is the host is included in this list. * * \param hostlist: pointer to a string that contains the list of the allowed host. * * \param sep: a string that keeps the separators used between the hosts (for example the * space character) in the host list. * * \param from: a sockaddr_storage structure, as it is returned by the accept() call. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return It returns: * - '1' if the host list is empty * - '0' if the host belongs to the host list (and therefore it is allowed to connect) * - '-1' in case the host does not belong to the host list (and therefore it is not allowed to connect * - '-2' in case or error. The error message is returned in the 'errbuf' variable. */ int sock_check_hostlist(char *hostlist, const char *sep, struct sockaddr_storage *from, char *errbuf, int errbuflen) { /* checks if the connecting host is among the ones allowed */ if ((hostlist) && (hostlist[0])) { char *token; /* temp, needed to separate items into the hostlist */ struct addrinfo *addrinfo, *ai_next; char *temphostlist; char *lasts; /* * The problem is that strtok modifies the original variable by putting '0' at the end of each token * So, we have to create a new temporary string in which the original content is kept */ temphostlist = strdup(hostlist); if (temphostlist == NULL) { sock_geterror("sock_check_hostlist(), malloc() failed", errbuf, errbuflen); return -2; } token = pcap_strtok_r(temphostlist, sep, &lasts); /* it avoids a warning in the compilation ('addrinfo used but not initialized') */ addrinfo = NULL; while (token != NULL) { struct addrinfo hints; int retval; addrinfo = NULL; memset(&hints, 0, sizeof(struct addrinfo)); hints.ai_family = PF_UNSPEC; hints.ai_socktype = SOCK_STREAM; retval = getaddrinfo(token, "0", &hints, &addrinfo); if (retval != 0) { if (errbuf) pcap_snprintf(errbuf, errbuflen, "getaddrinfo() %s", gai_strerror(retval)); SOCK_DEBUG_MESSAGE(errbuf); /* Get next token */ token = pcap_strtok_r(NULL, sep, &lasts); continue; } /* ai_next is required to preserve the content of addrinfo, in order to deallocate it properly */ ai_next = addrinfo; while (ai_next) { if (sock_cmpaddr(from, (struct sockaddr_storage *) ai_next->ai_addr) == 0) { free(temphostlist); freeaddrinfo(addrinfo); return 0; } /* * If we are here, it means that the current address does not matches * Let's try with the next one in the header chain */ ai_next = ai_next->ai_next; } freeaddrinfo(addrinfo); addrinfo = NULL; /* Get next token */ token = pcap_strtok_r(NULL, sep, &lasts); } if (addrinfo) { freeaddrinfo(addrinfo); addrinfo = NULL; } if (errbuf) pcap_snprintf(errbuf, errbuflen, "The host is not in the allowed host list. Connection refused."); free(temphostlist); return -1; } /* No hostlist, so we have to return 'empty list' */ return 1; } /* * \brief Compares two addresses contained into two sockaddr_storage structures. * * This function is useful to compare two addresses, given their internal representation, * i.e. an sockaddr_storage structure. * * The two structures do not need to be sockaddr_storage; you can have both 'sockaddr_in' and * sockaddr_in6, properly acsted in order to be compliant to the function interface. * * This function will return '0' if the two addresses matches, '-1' if not. * * \param first: a sockaddr_storage structure, (for example the one that is returned by an * accept() call), containing the first address to compare. * * \param second: a sockaddr_storage structure containing the second address to compare. * * \return '0' if the addresses are equal, '-1' if they are different. */ int sock_cmpaddr(struct sockaddr_storage *first, struct sockaddr_storage *second) { if (first->ss_family == second->ss_family) { if (first->ss_family == AF_INET) { if (memcmp(&(((struct sockaddr_in *) first)->sin_addr), &(((struct sockaddr_in *) second)->sin_addr), sizeof(struct in_addr)) == 0) return 0; } else /* address family is AF_INET6 */ { if (memcmp(&(((struct sockaddr_in6 *) first)->sin6_addr), &(((struct sockaddr_in6 *) second)->sin6_addr), sizeof(struct in6_addr)) == 0) return 0; } } return -1; } /* * \brief It gets the address/port the system picked for this socket (on connected sockets). * * It is used to return the address and port the server picked for our socket on the local machine. * It works only on: * - connected sockets * - server sockets * * On unconnected client sockets it does not work because the system dynamically chooses a port * only when the socket calls a send() call. * * \param sock: the connected socket currently opened. * * \param address: it contains the address that will be returned by the function. This buffer * must be properly allocated by the user. The address can be either literal or numeric depending * on the value of 'Flags'. * * \param addrlen: the length of the 'address' buffer. * * \param port: it contains the port that will be returned by the function. This buffer * must be properly allocated by the user. * * \param portlen: the length of the 'port' buffer. * * \param flags: a set of flags (the ones defined into the getnameinfo() standard socket function) * that determine if the resulting address must be in numeric / literal form, and so on. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return It returns '-1' if this function succeeds, '0' otherwise. * The address and port corresponding are returned back in the buffers 'address' and 'port'. * In any case, the returned strings are '0' terminated. * * \warning If the socket is using a connectionless protocol, the address may not be available * until I/O occurs on the socket. */ int sock_getmyinfo(SOCKET sock, char *address, int addrlen, char *port, int portlen, int flags, char *errbuf, int errbuflen) { struct sockaddr_storage mysockaddr; socklen_t sockaddrlen; sockaddrlen = sizeof(struct sockaddr_storage); if (getsockname(sock, (struct sockaddr *) &mysockaddr, &sockaddrlen) == -1) { sock_geterror("getsockname(): ", errbuf, errbuflen); return 0; } /* Returns the numeric address of the host that triggered the error */ return sock_getascii_addrport(&mysockaddr, address, addrlen, port, portlen, flags, errbuf, errbuflen); } /* * \brief It retrieves two strings containing the address and the port of a given 'sockaddr' variable. * * This function is basically an extended version of the inet_ntop(), which does not exist in * Winsock because the same result can be obtained by using the getnameinfo(). * However, differently from inet_ntop(), this function is able to return also literal names * (e.g. 'localhost') dependently from the 'Flags' parameter. * * The function accepts a sockaddr_storage variable (which can be returned by several functions * like bind(), connect(), accept(), and more) and it transforms its content into a 'human' * form. So, for instance, it is able to translate an hex address (stored in binary form) into * a standard IPv6 address like "::1". * * The behavior of this function depends on the parameters we have in the 'Flags' variable, which * are the ones allowed in the standard getnameinfo() socket function. * * \param sockaddr: a 'sockaddr_in' or 'sockaddr_in6' structure containing the address that * need to be translated from network form into the presentation form. This structure must be * zero-ed prior using it, and the address family field must be filled with the proper value. * The user must cast any 'sockaddr_in' or 'sockaddr_in6' structures to 'sockaddr_storage' before * calling this function. * * \param address: it contains the address that will be returned by the function. This buffer * must be properly allocated by the user. The address can be either literal or numeric depending * on the value of 'Flags'. * * \param addrlen: the length of the 'address' buffer. * * \param port: it contains the port that will be returned by the function. This buffer * must be properly allocated by the user. * * \param portlen: the length of the 'port' buffer. * * \param flags: a set of flags (the ones defined into the getnameinfo() standard socket function) * that determine if the resulting address must be in numeric / literal form, and so on. * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return It returns '-1' if this function succeeds, '0' otherwise. * The address and port corresponding to the given SockAddr are returned back in the buffers 'address' * and 'port'. * In any case, the returned strings are '0' terminated. */ int sock_getascii_addrport(const struct sockaddr_storage *sockaddr, char *address, int addrlen, char *port, int portlen, int flags, char *errbuf, int errbuflen) { socklen_t sockaddrlen; int retval; /* Variable that keeps the return value; */ retval = -1; #ifdef _WIN32 if (sockaddr->ss_family == AF_INET) sockaddrlen = sizeof(struct sockaddr_in); else sockaddrlen = sizeof(struct sockaddr_in6); #else sockaddrlen = sizeof(struct sockaddr_storage); #endif if ((flags & NI_NUMERICHOST) == 0) /* Check that we want literal names */ { if ((sockaddr->ss_family == AF_INET6) && (memcmp(&((struct sockaddr_in6 *) sockaddr)->sin6_addr, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", sizeof(struct in6_addr)) == 0)) { if (address) strlcpy(address, SOCKET_NAME_NULL_DAD, addrlen); return retval; } } if (getnameinfo((struct sockaddr *) sockaddr, sockaddrlen, address, addrlen, port, portlen, flags) != 0) { /* If the user wants to receive an error message */ if (errbuf) { sock_geterror("getnameinfo(): ", errbuf, errbuflen); errbuf[errbuflen - 1] = 0; } if (address) { strlcpy(address, SOCKET_NO_NAME_AVAILABLE, addrlen); address[addrlen - 1] = 0; } if (port) { strlcpy(port, SOCKET_NO_PORT_AVAILABLE, portlen); port[portlen - 1] = 0; } retval = 0; } return retval; } /* * \brief It translates an address from the 'presentation' form into the 'network' form. * * This function basically replaces inet_pton(), which does not exist in Winsock because * the same result can be obtained by using the getaddrinfo(). * An additional advantage is that 'Address' can be both a numeric address (e.g. '127.0.0.1', * like in inet_pton() ) and a literal name (e.g. 'localhost'). * * This function does the reverse job of sock_getascii_addrport(). * * \param address: a zero-terminated string which contains the name you have to * translate. The name can be either literal (e.g. 'localhost') or numeric (e.g. '::1'). * * \param sockaddr: a user-allocated sockaddr_storage structure which will contains the * 'network' form of the requested address. * * \param addr_family: a constant which can assume the following values: * - 'AF_INET' if we want to ping an IPv4 host * - 'AF_INET6' if we want to ping an IPv6 host * - 'AF_UNSPEC' if we do not have preferences about the protocol used to ping the host * * \param errbuf: a pointer to an user-allocated buffer that will contain the complete * error message. This buffer has to be at least 'errbuflen' in length. * It can be NULL; in this case the error cannot be printed. * * \param errbuflen: length of the buffer that will contains the error. The error message cannot be * larger than 'errbuflen - 1' because the last char is reserved for the string terminator. * * \return '-1' if the translation succeeded, '-2' if there was some non critical error, '0' * otherwise. In case it fails, the content of the SockAddr variable remains unchanged. * A 'non critical error' can occur in case the 'Address' is a literal name, which can be mapped * to several network addresses (e.g. 'foo.bar.com' => '10.2.2.2' and '10.2.2.3'). In this case * the content of the SockAddr parameter will be the address corresponding to the first mapping. * * \warning The sockaddr_storage structure MUST be allocated by the user. */ int sock_present2network(const char *address, struct sockaddr_storage *sockaddr, int addr_family, char *errbuf, int errbuflen) { int retval; struct addrinfo *addrinfo; struct addrinfo hints; memset(&hints, 0, sizeof(hints)); hints.ai_family = addr_family; if ((retval = sock_initaddress(address, "22222" /* fake port */, &hints, &addrinfo, errbuf, errbuflen)) == -1) return 0; if (addrinfo->ai_family == PF_INET) memcpy(sockaddr, addrinfo->ai_addr, sizeof(struct sockaddr_in)); else memcpy(sockaddr, addrinfo->ai_addr, sizeof(struct sockaddr_in6)); if (addrinfo->ai_next != NULL) { freeaddrinfo(addrinfo); if (errbuf) pcap_snprintf(errbuf, errbuflen, "More than one socket requested; using the first one returned"); return -2; } freeaddrinfo(addrinfo); return -1; }