X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;h=7207e528f8c1dd781858d88d8d1761782494c99f;hp=b2c9c43a81ad356ec021373c12d5c764fa5b76f4;hb=343a65bc48b4e0cda4d9a14afcd7e96cca9c5de9;hpb=d2a600590a2607d2bd729f3079aaec320efe7990 diff --git a/net.c b/net.c index b2c9c43a..7207e528 100644 --- a/net.c +++ b/net.c @@ -1,11 +1,17 @@ /* - * Copyright (C) 2005-2008 Andre Noll + * Copyright (C) 2005-2009 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ /** \file net.c Networking-related helper functions. */ +/* + * Since glibc 2.8, the _GNU_SOURCE feature test macro must be defined in order + * to obtain the definition of the ucred structure. + */ +#define _GNU_SOURCE + #include /* At least NetBSD needs these. */ @@ -20,6 +26,7 @@ #endif #include +#include #include "para.h" #include "error.h" @@ -85,6 +92,114 @@ void disable_crypt(int fd) crypt_data_array[fd].private_data = NULL; } +/** + * Match string as a candidate IPv4 address. + * + * \param address The string to match. + * \return True if \a address has "dot-quad" format. + */ +static bool is_v4_dot_quad(const char *address) +{ + bool result; + regex_t r; + + assert(!regcomp(&r, "^([0-9]+\\.){3}[0-9]+$", REG_EXTENDED|REG_NOSUB)); + result = regexec(&r, address, 0, NULL, 0) == 0; + regfree(&r); + return result; +} + +/** + * Perform basic syntax checking on the host-part of an URL: + * + * - Since ':' is invalid in IPv4 addresses and DNS names, the + * presence of ':' causes interpretation as IPv6 address; + * - next the first-match-wins algorithm from RFC 3986 is applied; + * - else the string is considered as DNS name, to be resolved later. + * + * \param host The host string to check. + * \return True if \a host passes the syntax checks. + * + * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5 + */ +static bool host_string_ok(const char *host) +{ + if (host == NULL || *host == '\0') + return false; + if (strchr(host, ':') != NULL) + return is_valid_ipv6_address(host); + if (is_v4_dot_quad(host)) + return is_valid_ipv4_address(host); + return true; +} + +/** + * Parse and validate URL string. + * + * The URL syntax is loosely based on RFC 3986, supporting one of + * - "["host"]"[:port] for native IPv6 addresses and + * - host[:port] for IPv4 hostnames and DNS names. + * + * Native IPv6 addresses must be enclosed in square brackets, since + * otherwise there is an ambiguity with the port separator `:'. + * The 'port' part is always considered to be a number; if absent, + * it is set to -1, to indicate that a default port is to be used. + * + * The following are valid examples: + * - 10.10.1.1 + * - 10.10.1.2:8000 + * - localhost + * - localhost:8001 + * - [::1]:8000 + * - [badc0de::1] + * + * \param url The URL string to take apart. + * \param host To return the copied host part of \a url. + * \param hostlen The maximum length of \a host. + * \param port To return the port number (if any) of \a url. + * + * \return Pointer to \a host, or NULL if failed. + * If NULL is returned, \a host and \a portnum are undefined. If no + * port number was present in \a url, \a portnum is set to -1. + * + * \sa RFC 3986, 3.2.2/3.2.3 + */ +char *parse_url(const char *url, + char *host, ssize_t hostlen, + int32_t *port) +{ + const char *o = url; + char *c = host, *end = c + (hostlen - 1); + + *port = -1; + + if (o == NULL || hostlen < 1) + goto failed; + + if (*o == '[') { + for (++o; (*c = *o == ']' ? '\0' : *o); c++, o++) + if (c == end) + goto failed; + + if (*o++ != ']' || (*o != '\0' && *o != ':')) + goto failed; + } else { + for (; (*c = *o == ':'? '\0' : *o); c++, o++) + if (c == end) + goto failed; + } + + if (*o == ':') + if (para_atoi32(++o, port) < 0 || + *port < 0 || *port > 0xffff) + goto failed; + + if (host_string_ok(host)) + return host; +failed: + *host = '\0'; + return NULL; +} /** * Determine the socket type for a given layer-4 protocol. @@ -157,9 +272,13 @@ int makesock(unsigned l3type, unsigned l4type, int passive, /* Set up address hint structure */ memset(&hints, 0, sizeof(hints)); hints.ai_family = l3type; - /* getaddrinfo does not really work well with SOCK_DCCP */ - if (socktype == SOCK_DGRAM || socktype == SOCK_STREAM) - hints.ai_socktype = socktype; + hints.ai_socktype = socktype; + /* + * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup + * (and only then) pretend to be UDP. + */ + if (l4type == IPPROTO_DCCP) + hints.ai_socktype = SOCK_DGRAM; /* only use addresses available on the host */ hints.ai_flags = AI_ADDRCONFIG; @@ -315,11 +434,31 @@ static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*, return host_and_port((struct sockaddr *)&ss, sslen); } +/** + * Look up the local side of a connected socket structure. + * + * \param sockfd The file descriptor of the socket. + * + * \return A pointer to a static buffer containing hostname an port. This + * buffer must not be freed by the caller. + * + * \sa remote_name(). + */ char *local_name(int sockfd) { return __get_sock_name(sockfd, getsockname); } +/** + * Look up the remote side of a connected socket structure. + * + * \param sockfd The file descriptor of the socket. + * + * \return Analogous to the return value of \ref local_name() but for the + * remote side. + * + * \sa local_name(). + */ char *remote_name(int sockfd) { return __get_sock_name(sockfd, getpeername); @@ -337,7 +476,7 @@ struct in_addr extract_v4_addr(const struct sockaddr_storage *ss) struct in_addr ia = {.s_addr = 0}; if (ss->ss_family == AF_INET) - ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr; + ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr; if (ss->ss_family == AF_INET6) { const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr; @@ -355,8 +494,8 @@ struct in_addr extract_v4_addr(const struct sockaddr_storage *ss) * \param len The length of \a buf. * * Check if encryption is available. If yes, encrypt the given buffer. Send - * out the buffer, encrypted or not, and try to resend the remaing part in case - * of short writes. + * out the buffer, encrypted or not, and try to resend the remaining part in + * case of short writes. * * \return Standard. */ @@ -623,7 +762,7 @@ int recv_cred_buffer(int fd, char *buf, size_t size) */ ssize_t send_cred_buffer(int sock, char *buf) { - char control[sizeof(struct cmsghdr) + 10]; + char control[sizeof(struct cmsghdr) + sizeof(struct ucred)]; struct msghdr msg; struct cmsghdr *cmsg; static struct iovec iov; @@ -724,10 +863,9 @@ int recv_cred_buffer(int fd, char *buf, size_t size) * * \return Positive if \a pattern was received, negative otherwise. * - * This function creates a buffer of size \a bufsize and tries - * to receive at most \a bufsize bytes from file descriptor \a fd. - * If at least \p strlen(\a pattern) bytes were received, the beginning of - * the received buffer is compared with \a pattern, ignoring case. + * This function tries to receive at most \a bufsize bytes from file descriptor + * \a fd. If at least \p strlen(\a pattern) bytes were received, the beginning + * of the received buffer is compared with \a pattern, ignoring case. * * \sa recv_buffer(), \sa strncasecmp(3). */ @@ -735,7 +873,7 @@ int recv_pattern(int fd, const char *pattern, size_t bufsize) { size_t len = strlen(pattern); char *buf = para_malloc(bufsize + 1); - int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize); + int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize + 1); if (n < len) goto out;