X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;h=ab6a98940b1e920eee7ee5e3f8f6b9bb33cf94b9;hp=312a68546f08bc5493699a9ae32d6a4b96164e13;hb=3f9051d22fcf6e968259946eaf521ac3daac470e;hpb=002731cd3938f3be6b71651e56c062af1adcdec0 diff --git a/net.c b/net.c index 312a6854..ab6a9894 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 +92,155 @@ void disable_crypt(int fd) crypt_data_array[fd].private_data = NULL; } +/** + * Parse and validate IPv4 address/netmask string. + * + * \param cidr Address in CIDR notation + * \param addr Copy of the IPv4 address part of \a cidr + * \param addrlen Size of \a addr in bytes + * \param netmask Value of the netmask part in \a cidr or the + * default of 32 if not specified. + * + * \return Pointer to \a addr if succesful, NULL on error. + * \sa RFC 4632 + */ +char *parse_cidr(const char *cidr, + char *addr, ssize_t addrlen, + int32_t *netmask) +{ + const char *o = cidr; + char *c = addr, *end = c + (addrlen - 1); + + *netmask = 0x20; + + if (cidr == NULL || addrlen < 1) + goto failed; + + for (o = cidr; (*c = *o == '/'? '\0' : *o); c++, o++) + if (c == end) + goto failed; + + if (*o == '/') + if (para_atoi32(++o, netmask) < 0 || + *netmask < 0 || *netmask > 0x20) + goto failed; + + if (is_valid_ipv4_address(addr)) + return addr; +failed: + *addr = '\0'; + return 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. @@ -319,11 +475,31 @@ 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); @@ -341,7 +517,7 @@ 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; @@ -359,8 +535,8 @@ 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. */ @@ -627,7 +803,7 @@ 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; @@ -755,142 +931,3 @@ 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; -}