* Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file net.c networking-related helper functions */
+/** \file net.c Networking-related helper functions. */
+
+#include <netdb.h>
#include "para.h"
#include "error.h"
static unsigned cda_size = 0;
/**
- * activate encryption for one file descriptor
+ * Activate encryption for one file descriptor.
*
- * \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 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.
*/
void enable_crypt(int fd, crypt_function *recv_f, crypt_function *send_f,
void *private_data)
}
/**
- * deactivate encryption for a given fd
+ * Deactivate encryption for a given fd.
*
- * \param fd the file descriptor
+ * \param fd The file descriptor.
*
* This must be called if and only if \p fd was activated via enable_crypt().
*/
/**
- * initialize a struct sockaddr_in
+ * Determine the socket type for a given layer-4 protocol.
*
- * \param addr A pointer to the struct to be initialized
- * \param port The port number to use
- * \param he The address to use
+ * \param l4type The symbolic name of the transport-layer protocol.
*
- * If \a he is null (server mode), \a addr->sin_addr is initialized with \p
- * INADDR_ANY. Otherwise, the address given by \a he is copied to addr.
+ * \sa ip(7), socket(2)
*/
-void init_sockaddr(struct sockaddr_in *addr, int port, const struct hostent *he)
+static inline int sock_type(const unsigned l4type)
{
- /* host byte order */
- addr->sin_family = AF_INET;
- /* short, network byte order */
- addr->sin_port = htons(port);
- if (he)
- addr->sin_addr = *((struct in_addr *)he->h_addr);
- else
- addr->sin_addr.s_addr = INADDR_ANY;
- /* zero the rest of the struct */
- memset(&addr->sin_zero, '\0', 8);
+ switch (l4type) {
+ case IPPROTO_UDP: return SOCK_DGRAM;
+ case IPPROTO_TCP: return SOCK_STREAM;
+ case IPPROTO_DCCP: return SOCK_DCCP;
+ }
+ return -1; /* not supported here */
}
-/*
- * send out a buffer, resend on short writes
+/**
+ * Pretty-print transport-layer name.
+ */
+static const char *layer4_name(const unsigned l4type)
+{
+ switch (l4type) {
+ case IPPROTO_UDP: return "UDP";
+ case IPPROTO_TCP: return "TCP";
+ case IPPROTO_DCCP: return "DCCP";
+ }
+ return "UNKNOWN PROTOCOL";
+}
+
+/**
+ * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
+ *
+ * @param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC)
+ * @param l4type The layer-4 type (\p IPPROTO_xxx).
+ * @param passive Whether this is a passive (1) or active (0) socket/
+ * @param host Remote or local hostname or IPv/6 address string.
+ * @param port_number Decimal port number.
+ *
+ * This creates a ready-made IPv4/v6 socket structure after looking up the necessary
+ * parameters. The interpretation of \a host depends on the value of \a passive:
+ * - on a passive socket host is interpreted as an interface IPv4/6 address
+ * (can be left NULL);
+ * - on an active socket, \a host is the peer DNS name or IPv4/6 address to connect to;
+ * - \a port_number is in either case the numeric port number (not service string).
+ * Furthermore, bind(2) is called on passive sockets, and connect(2) on active sockets.
+ * The algorithm tries all possible address combinations until it succeeds.
+ *
+ * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no matching
+ * connection could be set up (with details in the error log).
+ *
+ * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2)
+ */
+int makesock(unsigned l3type, unsigned l4type, int passive,
+ const char *host, unsigned short port_number)
+{
+ struct addrinfo *local = NULL, *src,
+ *remote = NULL, *dst, hints;
+ char *port = make_message("%u", port_number);
+ int rc, on = 1, sockfd = -1,
+ socktype = sock_type(l4type);
+
+ /*
+ * 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;
+
+ /* only use addresses available on the host */
+ hints.ai_flags = AI_ADDRCONFIG;
+ if (l3type == AF_INET6)
+ /* use v4-mapped-v6 if no v6 addresses found */
+ hints.ai_flags |= AI_V4MAPPED | AI_ALL;
+
+ if (passive && host == NULL)
+ hints.ai_flags |= AI_PASSIVE;
+
+ /*
+ * Obtain local/remote address information
+ */
+ if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
+ PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
+ layer4_name(l4type),
+ host? : (passive? "[loopback]" : "[localhost]"),
+ port, gai_strerror(rc));
+ return -E_ADDRESS_LOOKUP;
+ }
+
+ /*
+ * Iterate over all src/dst combination, exhausting dst first
+ */
+ for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
+ if (src && dst && src->ai_family == AF_INET
+ && dst->ai_family == AF_INET6) /* v4 -> v6 is not possible */
+ goto get_next_dst;
+
+ sockfd = socket(src ? src->ai_family : dst->ai_family, socktype, l4type);
+ if (sockfd < 0)
+ goto get_next_dst;
+
+ /*
+ * Set those options that need to be set before establishing the connection
+ */
+ /* Reuse the address on passive (listening) sockets to avoid failure on restart */
+ if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) {
+ PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n", strerror(errno));
+ return -ERRNO_TO_PARA_ERROR(errno);
+ }
+
+ if (src) {
+ if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
+ close(sockfd);
+ goto get_next_src;
+ }
+ if (!dst)
+ break; /* bind-only completed successfully */
+ }
+
+ if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
+ break; /* connection completed successfully */
+ close(sockfd);
+get_next_dst:
+ if (dst && (dst = dst->ai_next))
+ continue;
+get_next_src:
+ if (src && (src = src->ai_next))
+ dst = remote; /* restart inner loop */
+ }
+ if (local)
+ freeaddrinfo(local);
+ if (remote)
+ freeaddrinfo(remote);
+
+ if (src == NULL && dst == NULL) {
+ PARA_ERROR_LOG("can not create %s socket %s#%s.\n", layer4_name(l4type),
+ host? : (passive? "[loopback]" : "[localhost]"), port);
+ return -ERRNO_TO_PARA_ERROR(errno);
+ }
+ return sockfd;
+}
+
+/**
+ * Create a passive / listening socket.
+ * \param l3type The network-layer type (\p AF_xxx)
+ * \param l4type The transport-layer type (\p IPPROTO_xxx).
+ * \param port The decimal port number to listen on.
+ *
+ * \return Positive integer (socket descriptor) on success, negative value otherwise.
+ * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
+ */
+int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
+{
+ int ret, fd = makesock(l3type, l4type, 1, NULL, port);
+
+ if (fd > 0) {
+ ret = listen(fd, BACKLOG);
+ if (ret < 0) {
+ close(fd);
+ return -ERRNO_TO_PARA_ERROR(errno);
+ }
+ PARA_INFO_LOG("listening on %s port %u, fd %d\n",
+ layer4_name(l4type), port, fd);
+ }
+ return fd;
+}
+
+/**
+ * Print numeric host and port number (beware - uses static char).
+ * \param sa The IPv4/IPv6 socket address to use.
+ * \param len The length of \p sa.
+ *
+ * \sa getnameinfo(3)
+ */
+char *host_and_port(struct sockaddr *sa, socklen_t len)
+{
+ static char output[NI_MAXHOST + NI_MAXSERV + 2];
+ char hbuf[NI_MAXHOST],
+ sbuf[NI_MAXSERV];
+ int ret;
+
+ ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
+ NI_NUMERICHOST | NI_NUMERICSERV);
+ if (ret) {
+ PARA_WARNING_LOG("hostname lookup error (%s).\n", gai_strerror(ret));
+ sprintf(output, "(unknown)");
+ } else {
+ sprintf(output, "%s#%s", hbuf, sbuf);
+ }
+ return output;
+}
+
+/**
+ * Look up the local or remote side of a connected socket structure.
+ * \param fd The socket descriptor of the connected socket.
+ * \param getname Either \fn getsockname() for local, or \fn getpeername() for remote side.
*
- * \param fd the file descriptor
- * \param buf The buffer to be sent
- * \param len The length of \a buf
+ * \return A static character string identifying hostname and port of the chosen side
+ * \sa getsockname(2), getpeername(2)
+ */
+static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*, socklen_t *))
+{
+ struct sockaddr_storage ss;
+ socklen_t sslen = sizeof(ss);
+
+ if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
+ static char *dont_know = "(don't know)";
+ PARA_ERROR_LOG("can not determine address from fd %d: %s\n", fd, strerror(errno));
+ return dont_know;
+ }
+
+ return host_and_port((struct sockaddr *)&ss, sslen);
+}
+
+char *local_name(int sockfd)
+{
+ return __get_sock_name(sockfd, getsockname);
+}
+
+char *remote_name(int sockfd)
+{
+ return __get_sock_name(sockfd, getpeername);
+}
+
+/*
+ * Send out a buffer, resend on short writes.
*
- * Due to circumstances beyond your control, the kernel might not send all the
- * data out in one chunk, and now, my friend, it's up to us to get the data out
- * there (Beej's Guide to Network Programming).
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
*
- * \return This function returns 1 on success and \a -E_SEND on errors. The
- * number of bytes actually sent is stored upon successful return in \a len.
+ * \return Standard. In any case, the number of bytes actually sent is stored
+ * in \a len.
*/
static int sendall(int fd, const char *buf, size_t *len)
{
- size_t total = 0, bytesleft = *len; /* how many we have left to send */
- int n = -1;
-
- while (total < *len) {
- n = send(fd, buf + total, bytesleft, 0);
- if (n == -1)
- break;
- total += n;
- bytesleft -= n;
- if (total < *len)
- PARA_DEBUG_LOG("short write (%zd byte(s) left)\n",
- *len - total);
+ size_t total = *len;
+
+ assert(total);
+ *len = 0;
+ while (*len < total) {
+ int ret = send(fd, buf + *len, total - *len, 0);
+ if (ret == -1)
+ return -ERRNO_TO_PARA_ERROR(errno);
+ *len += ret;
}
- *len = total; /* return number actually sent here */
- return n == -1? -E_SEND : 1; /* return 1 on success */
+ return 1;
}
/**
* out the buffer, encrypted or not, and try to resend the remaing part in case
* of short writes.
*
- * \return Positive on success, \p -E_SEND on errors.
+ * \return Standard.
*/
int send_bin_buffer(int fd, const char *buf, size_t len)
{
}
/**
- * encrypt and send null terminated buffer.
+ * Encrypt and send null terminated buffer.
*
- * \param fd the file descriptor
- * \param buf the null-terminated buffer to be send
+ * \param fd The file descriptor.
+ * \param buf The null-terminated buffer to be send.
*
* This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
*
- * \return Positive on success, \p -E_SEND on errors.
+ * \return Standard.
*/
int send_buffer(int fd, const char *buf)
{
/**
- * send and encrypt a buffer given by a format string
+ * Send and encrypt a buffer given by a format string.
*
- * \param fd the file descriptor
- * \param fmt a format string
+ * \param fd The file descriptor.
+ * \param fmt A format string.
*
- * \return Positive on success, \p -E_SEND on errors.
+ * \return Standard.
*/
__printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
{
}
/**
- * receive and decrypt.
+ * Receive and decrypt.
*
- * \param fd the file descriptor
- * \param buf the buffer to write the decrypted data to
- * \param size the size of \a buf
+ * \param fd The file descriptor.
+ * \param buf The buffer to write the decrypted data to.
+ * \param size The size of \a buf.
*
- * Receive at most \a size bytes from filedescriptor fd. If encryption is
+ * Receive at most \a size bytes from file descriptor \a fd. If encryption is
* available, decrypt the received buffer.
*
- * \return The number of bytes received on success. On receive errors, -E_RECV
- * is returned. On crypt errors, the corresponding crypt error number is
- * returned.
+ * \return The number of bytes received on success, negative on errors.
*
* \sa recv(2)
*/
} else
n = recv(fd, buf, size, 0);
if (n == -1)
- n = -E_RECV;
+ return -ERRNO_TO_PARA_ERROR(errno);
return n;
}
/**
- * receive, decrypt and write terminating NULL byte
+ * Receive, decrypt and write terminating NULL byte.
*
- * \param fd the file descriptor
- * \param buf the buffer to write the decrypted data to
- * \param size the size of \a buf
+ * \param fd The file descriptor.
+ * \param buf The buffer to write the decrypted data to.
+ * \param size The size of \a buf.
*
* Read and decrypt 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().
+ * \return The return value of the underlying call to \a recv_bin_buffer().
*
* \sa recv_bin_buffer()
*/
{
int n;
- if (!size)
- return -E_RECV;
+ assert(size);
n = recv_bin_buffer(fd, buf, size - 1);
if (n >= 0)
buf[n] = '\0';
}
/**
- * wrapper around gethostbyname
- *
- * \param host hostname or IPv4 address
- * \param ret the hostent structure is returned here
- *
- * \return positive on success, negative on errors. On success, \a ret
- * contains the return value of the underlying gethostbyname() call.
- *
- * \sa gethostbyname(2)
- */
-int get_host_info(char *host, struct hostent **ret)
-{
- PARA_INFO_LOG("getting host info of %s\n", host);
- /* FIXME: gethostbyname() is obsolete */
- *ret = gethostbyname(host);
- return *ret? 1 : -E_HOST_INFO;
-}
-
-/**
- * A wrapper around socket(2).
- *
- * \param domain The communication domain that selects the protocol family.
- *
- * \return The socket fd on success, -E_SOCKET on errors.
- *
- * Create an IPv4 socket for sequenced, reliable, two-way, connection-based
- * byte streams.
- *
- * \sa socket(2).
- */
-int get_stream_socket(int domain)
-{
- int socket_fd;
-
- if ((socket_fd = socket(domain, SOCK_STREAM, 0)) == -1)
- return -E_SOCKET;
- return socket_fd;
-}
-
-/**
- * paraslash's wrapper around the accept system call
+ * Wrapper around the accept system call.
*
- * \param fd the listening socket
- * \param addr structure which is filled in with the address of the peer socket
- * \param size should contain the size of the structure pointed to by \a addr
+ * \param fd The listening socket.
+ * \param addr Structure which is filled in with the address of the peer socket.
+ * \param size Should contain the size of the structure pointed to by \a addr.
*
* Accept incoming connections on \a addr. Retry if interrupted.
*
- * \return The new file descriptor on success, \a -E_ACCEPT on errors.
+ * \return The new file descriptor on success, negative on errors.
*
* \sa accept(2).
*/
do
new_fd = accept(fd, (struct sockaddr *) addr, &size);
while (new_fd < 0 && errno == EINTR);
- return new_fd < 0? -E_ACCEPT : new_fd;
-}
-
-static int setserversockopts(int socket_fd)
-{
- int yes = 1;
-
- if (setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &yes,
- sizeof(int)) == -1)
- return -E_SETSOCKOPT;
- return 1;
+ return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
}
/**
* \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
* than \p UNIX_PATH_MAX.
*/
-int init_unix_addr(struct sockaddr_un *u, const char *name)
+static int init_unix_addr(struct sockaddr_un *u, const char *name)
{
if (strlen(name) >= UNIX_PATH_MAX)
return -E_NAME_TOO_LONG;
* \param unix_addr Pointer to the \p AF_UNIX socket structure.
* \param mode The desired mode of the socket.
*
- * This functions creates a local socket for sequenced, reliable,
+ * This function creates a local socket for sequenced, reliable,
* two-way, connection-based byte streams.
*
* \return The file descriptor, on success, negative on errors.
ret = init_unix_addr(unix_addr, name);
if (ret < 0)
return ret;
- fd = socket(PF_UNIX, SOCK_STREAM, 0);
- if (fd < 0)
- return -E_SOCKET;
- ret = -E_BIND;
- if (bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX) < 0)
+ ret = socket(PF_UNIX, SOCK_STREAM, 0);
+ if (ret < 0)
+ return -ERRNO_TO_PARA_ERROR(errno);
+ fd = ret;
+ ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
+ if (ret < 0) {
+ ret = -ERRNO_TO_PARA_ERROR(errno);
goto err;
+ }
ret = -E_CHMOD;
if (chmod(name, mode) < 0)
goto err;
return ret;
}
+/**
+ * Prepare, create, and connect to a Unix domain socket for local communication.
+ *
+ * \param name The socket pathname.
+ *
+ * This function creates a local socket for sequenced, reliable, two-way,
+ * connection-based byte streams.
+ *
+ * \return The file descriptor, on success, negative on errors.
+ *
+ * \sa create_local_socket(), unix(7), connect(2)
+ */
+int create_remote_socket(const char *name)
+{
+ struct sockaddr_un unix_addr;
+ int fd, ret;
+
+ ret = init_unix_addr(&unix_addr, name);
+ if (ret < 0)
+ return ret;
+ fd = socket(PF_UNIX, SOCK_STREAM, 0);
+ if (fd < 0)
+ return -ERRNO_TO_PARA_ERROR(errno);
+ if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
+ ret = -ERRNO_TO_PARA_ERROR(errno);
+ goto err;
+ }
+ return fd;
+err:
+ close(fd);
+ return ret;
+}
+
#ifndef HAVE_UCRED
ssize_t send_cred_buffer(int sock, char *buf)
{
* \param buf the buffer to be sent
*
* \return On success, this call returns the number of characters sent. On
- * error, \p -E_SENDMSG ist returned.
+ * error, \p -E_SENDMSG is returned.
*
* \sa okir's Black Hats Manual
* \sa sendmsg(2)
}
#endif /* HAVE_UCRED */
-/** how many pending connections queue will hold */
-#define BACKLOG 10
-
-/**
- * create a socket, bind it and listen
- *
- * \param port the tcp port to listen on
- *
- * \return The file descriptor of the created socket, negative
- * on errors.
- *
- * \sa get_stream_socket()
- * \sa setsockopt(2)
- * \sa bind(2)
- * \sa listen(2)
- */
-int init_tcp_socket(int port)
-{
- struct sockaddr_in my_addr;
- int fd, ret = get_stream_socket(AF_INET);
-
- if (ret < 0)
- return ret;
- fd = ret;
- ret = setserversockopts(fd);
- if (ret < 0)
- goto err;
- init_sockaddr(&my_addr, port, NULL);
- ret = -E_BIND;
- if (bind(fd, (struct sockaddr *)&my_addr,
- sizeof(struct sockaddr)) == -1) {
- PARA_CRIT_LOG("bind error: %s\n", strerror(errno));
- goto err;
- }
- ret = -E_LISTEN;
- if (listen(fd, BACKLOG) == -1)
- goto err;
- PARA_INFO_LOG("listening on port %d, fd %d\n", port, fd);
- return fd;
-err:
- close(fd);
- return ret;
-}
-
/**
* receive a buffer and check for a pattern
*
projects / paraslash.git / blobdiff