X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;h=00844d735c033e73a20b8a975e0bf9db142d2600;hp=312a68546f08bc5493699a9ae32d6a4b96164e13;hb=3010ef96e10cb15d423eef8f9802fbed78744393;hpb=002731cd3938f3be6b71651e56c062af1adcdec0 diff --git a/net.c b/net.c index 312a6854..00844d73 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. */ @@ -20,71 +26,166 @@ #endif #include +#include +#include #include "para.h" #include "error.h" +#include "crypt.h" #include "net.h" #include "string.h" #include "fd.h" +/** + * 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; +} -/** Information about one encrypted connection. */ -struct crypt_data { - /** Function used to decrypt received data. */ - crypt_function *recv; - /** Function used to encrypt data to be sent. */ - crypt_function *send; - /** - * Context-dependent data (crypt keys), passed verbatim to the above - * crypt functions. - */ - void *private_data; -}; -/** Array holding per fd crypt data. */ -static struct crypt_data *crypt_data_array; -/** Current size of the crypt data array. */ -static unsigned cda_size = 0; /** - * Activate encryption for one file descriptor. + * Match string as a candidate IPv4 address. * - * \param fd The file descriptor. - * \param recv_f The function used for decrypting received data. - * \param send_f The function used for encrypting before sending. - * \param private_data User data supplied by the caller. + * \param address The string to match. + * \return True if \a address has "dot-quad" format. */ -void enable_crypt(int fd, crypt_function *recv_f, crypt_function *send_f, - void *private_data) +static bool is_v4_dot_quad(const char *address) { - if (fd + 1 > cda_size) { - crypt_data_array = para_realloc(crypt_data_array, - (fd + 1) * sizeof(struct crypt_data)); - memset(crypt_data_array + cda_size, 0, - (fd + 1 - cda_size) * sizeof(struct crypt_data)); - cda_size = fd + 1; - } - crypt_data_array[fd].recv = recv_f; - crypt_data_array[fd].send = send_f; - crypt_data_array[fd].private_data = private_data; - PARA_INFO_LOG("rc4 encryption activated for fd %d\n", fd); + bool result; + regex_t r; + + assert(para_regcomp(&r, "^([0-9]+\\.){3}[0-9]+$", + REG_EXTENDED | REG_NOSUB) >= 0); + result = regexec(&r, address, 0, NULL, 0) == 0; + regfree(&r); + return result; } /** - * Deactivate encryption for a given fd. + * Perform basic syntax checking on the host-part of an URL: * - * \param fd The file descriptor. + * - 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. * - * This must be called if and only if \p fd was activated via enable_crypt(). + * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5 */ -void disable_crypt(int fd) +static bool host_string_ok(const char *host) { - if (cda_size < fd + 1) - return; - crypt_data_array[fd].recv = NULL; - crypt_data_array[fd].send = NULL; - crypt_data_array[fd].private_data = NULL; + 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 +420,31 @@ 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 +462,7 @@ 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; @@ -352,41 +473,26 @@ struct in_addr extract_v4_addr(const struct sockaddr_storage *ss) } /** - * Encrypt and send a binary buffer. + * Send a binary buffer. * * \param fd The file descriptor. - * \param buf The buffer to be encrypted and sent. + * \param buf The buffer to be sent. * \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. + * Send out the buffer and try to resend the remaining part in case of short + * writes. * * \return Standard. */ int send_bin_buffer(int fd, const char *buf, size_t len) { - int ret; - crypt_function *cf = NULL; - if (!len) PARA_CRIT_LOG("len == 0\n"); - if (fd + 1 <= cda_size) - cf = crypt_data_array[fd].send; - if (cf) { - void *private = crypt_data_array[fd].private_data; - /* RC4 may write more than len to the output buffer */ - unsigned char *outbuf = para_malloc(ROUND_UP(len, 8)); - (*cf)(len, (unsigned char *)buf, outbuf, private); - ret = write_all(fd, (char *)outbuf, &len); - free(outbuf); - } else - ret = write_all(fd, buf, &len); - return ret; + return write_all(fd, buf, &len); } /** - * Encrypt and send null terminated buffer. + * Send a \p NULL-terminated buffer. * * \param fd The file descriptor. * \param buf The null-terminated buffer to be send. @@ -400,9 +506,8 @@ int send_buffer(int fd, const char *buf) return send_bin_buffer(fd, buf, strlen(buf)); } - /** - * Send and encrypt a buffer given by a format string. + * Send a buffer given by a format string. * * \param fd The file descriptor. * \param fmt A format string. @@ -421,51 +526,37 @@ __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...) } /** - * Receive and decrypt. + * Receive data from a file descriptor. * * \param fd The file descriptor. - * \param buf The buffer to write the decrypted data to. + * \param buf The buffer to write the data to. * \param size The size of \a buf. * - * Receive at most \a size bytes from file descriptor \a fd. If encryption is - * available, decrypt the received buffer. + * Receive at most \a size bytes from file descriptor \a fd. * - * \return The number of bytes received on success, negative on errors. + * \return The number of bytes received on success, negative on errors, zero if + * the peer has performed an orderly shutdown. * - * \sa recv(2) + * \sa recv(2). */ __must_check int recv_bin_buffer(int fd, char *buf, size_t size) { ssize_t n; - crypt_function *cf = NULL; - - if (fd + 1 <= cda_size) - cf = crypt_data_array[fd].recv; - if (cf) { - unsigned char *tmp = para_malloc(size); - void *private = crypt_data_array[fd].private_data; - n = recv(fd, tmp, size, 0); - if (n > 0) { - size_t numbytes = n; - unsigned char *b = (unsigned char *)buf; - (*cf)(numbytes, tmp, b, private); - } - free(tmp); - } else - n = recv(fd, buf, size, 0); + + n = recv(fd, buf, size, 0); if (n == -1) return -ERRNO_TO_PARA_ERROR(errno); return n; } /** - * Receive, decrypt and write terminating NULL byte. + * Receive and write terminating NULL byte. * * \param fd The file descriptor. - * \param buf The buffer to write the decrypted data to. + * \param buf The buffer to write the data to. * \param size The size of \a buf. * - * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and + * Read at most \a size - 1 bytes from file descriptor \a fd and * write a NULL byte at the end of the received data. * * \return The return value of the underlying call to \a recv_bin_buffer(). @@ -627,7 +718,7 @@ 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; @@ -747,150 +838,12 @@ int recv_pattern(int fd, const char *pattern, size_t bufsize) ret = 1; out: if (ret < 0) { - PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n, - pattern); + PARA_NOTICE_LOG("did not receive pattern '%s'\n", pattern); if (n > 0) - PARA_NOTICE_LOG("recvd: %s\n", buf); + PARA_NOTICE_LOG("recvd %d bytes: %s\n", n, buf); + else if (n < 0) + PARA_NOTICE_LOG("%s\n", para_strerror(-n)); } 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; -}