X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;h=88b3e3cc8aee0b2fadfd7783c763b062b8ac0d24;hp=312a68546f08bc5493699a9ae32d6a4b96164e13;hb=36bc7580a5ddee8f6e46bccfea7519291f372f0f;hpb=6bdac07456cb5872f824028912d1049883a9c21f diff --git a/net.c b/net.c index 312a6854..88b3e3cc 100644 --- a/net.c +++ b/net.c @@ -6,6 +6,12 @@ /** \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. @@ -755,142 +870,3 @@ out: free(buf); return ret; } - -static int resolve(const char *hostname, unsigned short port, - struct sockaddr_in *addr) -{ - struct hostent *host; - - assert(hostname); - host = gethostbyname(hostname); - if (!host) - return -ERRNO_TO_PARA_ERROR(h_errno); - if (addr) { - memcpy(&addr->sin_addr, host->h_addr_list[0], host->h_length); - addr->sin_port = port; - } - return 1; -} - -/* - * Create an UDP socket. - * - * If the given address is a multicast adress, the socket will be set - * to use the multicast TTL ttl and sets the datagrams to loop back. - * - * \return The fd of the socket on success, negative on errors. - */ -static int create_udp_socket(struct sockaddr_in *addr, - unsigned short port, unsigned char ttl) -{ - int ret, fd, yes = 1; - - assert(addr); - ret = socket(PF_INET, SOCK_DGRAM, 0); - if (ret < 0) - return -ERRNO_TO_PARA_ERROR(errno); - fd = ret; - /* reuse addresses */ - ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)); - if (ret < 0) { - ret = -ERRNO_TO_PARA_ERROR(errno); - goto err; - } - addr->sin_family = AF_INET; - addr->sin_port = htons(port); - /* set the TTL and turn on multicast loop */ - if (IN_MULTICAST(htonl(addr->sin_addr.s_addr))) { - unsigned char loop = 1; - ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, - sizeof(ttl)); - if (ret < 0) { - ret = -ERRNO_TO_PARA_ERROR(errno); - goto err; - } - ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, - sizeof(loop)); - if (ret < 0) { - ret = -ERRNO_TO_PARA_ERROR(errno); - goto err; - } - } - return fd; -err: - close(fd); - return ret; -} - -/** - * Create and connect a sending UDP socket. - * - * \param hostname Where to send to (name or IPv4 address). - * \param port The udp port to use. - * \param ttl Time to live (only relevant for multicast). - * - * \return The fd of the socket on success, negative on error. - */ -int create_udp_send_socket(char *hostname, unsigned short port, - unsigned char ttl) -{ - struct sockaddr_in addr; - int fd, ret = resolve(hostname, port, &addr); - - if (ret < 0) - return ret; - ret = create_udp_socket(&addr, port, ttl); - if (ret < 0) - return ret; - fd = ret; - ret = connect(fd, (struct sockaddr *)&addr, sizeof(addr)); - if (ret >= 0) - return fd; - ret = -ERRNO_TO_PARA_ERROR(errno); - close(fd); - return ret; -} - -/** - * Create and bind a receiving UDP socket. - * - * Bind the created UDP socket to \a hostname, and add multicast membership if - * hostname is a multicast hostname. - * - * \param hostname Name or IPv4 address to receive from. - * \param port The udp port. - * - * \return The fd of the socket on success, negative on errors. - */ -int create_udp_recv_socket(char *hostname, unsigned short port) -{ - struct sockaddr_in addr; - int fd, ret = resolve(hostname, port, &addr); - - if (ret < 0) - memset(&addr.sin_addr, 0, sizeof(addr.sin_addr)); - ret = create_udp_socket(&addr, port, 1); - if (ret < 0) - return ret; - fd = ret; - ret = bind(fd, (struct sockaddr *)&addr, sizeof(addr)); - if (ret < 0) { - ret = -ERRNO_TO_PARA_ERROR(errno); - goto err; - } - /* Add multicast membership */ - if (IN_MULTICAST(htonl(addr.sin_addr.s_addr))) { - struct ip_mreq mreq; - - mreq.imr_multiaddr.s_addr = addr.sin_addr.s_addr; - mreq.imr_interface.s_addr = htonl(INADDR_ANY); - ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, - &mreq, sizeof(mreq)); - if (ret < 0) { - ret = -ERRNO_TO_PARA_ERROR(errno); - goto err; - } - } - return fd; -err: - close(fd); - return ret; -}