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Diffstat (limited to 'sockutils.c')
| -rw-r--r-- | sockutils.c | 1230 |
1 files changed, 1230 insertions, 0 deletions
diff --git a/sockutils.c b/sockutils.c new file mode 100644 index 000000000000..c05ff1a1b58b --- /dev/null +++ b/sockutils.c @@ -0,0 +1,1230 @@ +/* + * 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 "config.h" +#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 <string.h> /* for strerror() */ +#include <errno.h> /* for the errno variable */ +#include <stdio.h> /* for the stderr file */ +#include <stdlib.h> /* for malloc() and free() */ +#ifdef HAVE_LIMITS_H +#include <limits.h> +#else +#define INT_MAX 2147483647 +#endif + +#include "portability.h" +#include "sockutils.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)" + +/**************************************************** + * * + * Locally defined functions * + * * + ****************************************************/ + +static int sock_ismcastaddr(const struct sockaddr *saddr); + +/**************************************************** + * * + * Function bodies * + * * + ****************************************************/ + +/* + * \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 + int retval; + int code; + TCHAR message[SOCK_ERRBUF_SIZE]; /* It will be char (if we're using ascii) or wchar_t (if we're using unicode) */ + + if (errbuf == NULL) + return; + + code = GetLastError(); + + retval = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS | + FORMAT_MESSAGE_MAX_WIDTH_MASK, + NULL, code, 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"); + return; + } + else + { + if ((caller) && (*caller)) + pcap_snprintf(errbuf, errbuflen, "%s%s (code %d)", caller, message, code); + else + pcap_snprintf(errbuf, errbuflen, "%s (code %d)", message, code); + } +#else + char *message; + + if (errbuf == NULL) + return; + + message = strerror(errno); + + if ((caller) && (*caller)) + pcap_snprintf(errbuf, errbuflen, "%s%s (code %d)", caller, message, errno); + else + pcap_snprintf(errbuf, errbuflen, "%s (code %d)", message, errno); +#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. + */ +int sock_init(char *errbuf, int errbuflen) +{ +#ifdef _WIN32 + 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++; +#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, '0' 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; + + sock = socket(addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol); + if (sock == -1) + { + sock_geterror("socket(): ", errbuf, errbuflen); + return -1; + } + + + /* This is a server socket */ + if (server) + { +#ifdef BSD + /* + * Force the use of IPv6-only addresses; in BSD you can accept both v4 and v6 + * connections if you have a "NULL" pointer as the nodename in the getaddrinfo() + * This behavior is not clear in the RFC 2553, so each system implements the + * bind() differently from this point of view + */ + if (addrinfo->ai_family == PF_INET6) + { + int on; + + if (setsockopt(sock, IPPROTO_IPV6, IPV6_BINDV6ONLY, (char *)&on, sizeof (int)) == -1) + { + if (errbuf) + pcap_snprintf(errbuf, errbuflen, "setsockopt(IPV6_BINDV6ONLY)"); + return -1; + } + } +#endif + + /* 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); + return -1; + } + + if (addrinfo->ai_socktype == SOCK_STREAM) + if (listen(sock, nconn) == -1) + { + sock_geterror("listen(): ", errbuf, errbuflen); + return -1; + } + + /* 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 -1; + } + 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"); + 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"); + 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 some errors occurred. The error message is returned + * in the 'errbuf' variable. + */ +int sock_send(SOCKET socket, const char *buffer, int size, char *errbuf, int errbuflen) +{ + int nsent; + +send: +#ifdef linux + /* + * Another pain... in Linux there's this flag + * MSG_NOSIGNAL + * Requests not to send SIGPIPE on errors on stream-oriented + * sockets when the other end breaks the connection. + * The EPIPE error is still returned. + */ + nsent = send(socket, buffer, size, MSG_NOSIGNAL); +#else + nsent = send(socket, buffer, size, 0); +#endif + + if (nsent == -1) + { + sock_geterror("send(): ", errbuf, errbuflen); + return -1; + } + + if (nsent != size) + { + size -= nsent; + buffer += nsent; + goto send; + } + + 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 receiveall: if '0' (or SOCK_RECEIVEALL_NO), it returns as soon as some data + * is ready; otherwise, (or SOCK_RECEIVEALL_YES) it waits until 'size' data has been + * received (in case the socket does not have enough data available). + * + * \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. + */ + +/* + * On UN*X, recv() returns ssize_t. + * On Windows, there *is* no ssize_t, and it returns an int. + * Define ssize_t as int on Windows so we can use it as the return value + * from recv(). + */ +#ifdef _WIN32 +typedef int ssize_t; +#endif + +int sock_recv(SOCKET sock, void *buffer, size_t size, int receiveall, + char *errbuf, int errbuflen) +{ + char *bufp = buffer; + int remaining; + ssize_t nread; + + if (size == 0) + { + SOCK_ASSERT("I have been requested to read zero bytes", 1); + return 0; + } + if (size > INT_MAX) + { + 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 (errbuf) + { + pcap_snprintf(errbuf, errbuflen, + "The other host terminated the connection."); + } + return -1; + } + + /* + * Do we want to read the amount requested, or just return + * what we got? + */ + if (!receiveall) + { + /* + * Just return what we got. + */ + return (int) nread; + } + + bufp += nread; + remaining -= nread; + + if (remaining == 0) + return (int) size; + } +} + +/* + * \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_ASSERT("I'm currently discarding data\n", 1); + + 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_ASSERT(errbuf, 1); + + /* 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); + 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; + } + else + { + /* Returns the numeric address of the host that triggered the error */ + return sock_getascii_addrport(&mysockaddr, address, addrlen, port, portlen, flags, errbuf, errbuflen); + } + + return 0; +} + +/* + * \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; +} |