X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;h=fa48e54f3f8525f26c716ef88784739ecd82a1fb;hp=92ae217d6b4bf7cdc438ff018774f9c0d9bdbc03;hb=e5f02e0748de02eabfb8e0746af09eb676ec1dc0;hpb=e90440367f744a7723b201a95888e66f070ffa92

diff --git a/net.c b/net.c
index 92ae217d..fa48e54f 100644
--- a/net.c
+++ b/net.c
@@ -380,8 +380,8 @@ int makesock(unsigned l4type, bool passive,
 	     const char *host, uint16_t port_number,
 	     struct flowopts *fo)
 {
-	struct addrinfo *local = NULL, *src,
-			*remote = NULL, *dst, hints;
+	struct addrinfo *local = NULL, *src = NULL, *remote = NULL,
+		*dst = NULL, hints;
 	unsigned int	l3type = AF_UNSPEC;
 	int		rc, on = 1, sockfd = -1,
 			socktype = sock_type(l4type);
@@ -414,7 +414,8 @@ int makesock(unsigned l4type, bool passive,
 				layer4_name(l4type),
 				host? host : (passive? "[loopback]" : "[localhost]"),
 				port, gai_strerror(rc));
-		return -E_ADDRESS_LOOKUP;
+		rc = -E_ADDRESS_LOOKUP;
+		goto out;
 	}
 
 	/* Iterate over all src/dst combination, exhausting dst first */
@@ -439,7 +440,8 @@ int makesock(unsigned l4type, bool passive,
 			close(sockfd);
 			PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
 				       strerror(rc));
-			return -ERRNO_TO_PARA_ERROR(rc);
+			rc = -ERRNO_TO_PARA_ERROR(rc);
+			break;
 		}
 		flowopt_setopts(sockfd, fo);
 
@@ -462,6 +464,7 @@ get_next_src:
 		if (src && (src = src->ai_next)) /* restart inner loop */
 			dst = remote;
 	}
+out:
 	if (local)
 		freeaddrinfo(local);
 	if (remote)
@@ -469,11 +472,12 @@ get_next_src:
 	flowopt_cleanup(fo);
 
 	if (src == NULL && dst == NULL) {
-		rc = errno;
+		if (rc >= 0)
+			rc = -E_MAKESOCK;
 		PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
 			layer4_name(l4type), host? host : (passive?
 			"[loopback]" : "[localhost]"), port);
-		return -ERRNO_TO_PARA_ERROR(rc);
+		return rc;
 	}
 	return sockfd;
 }
@@ -521,6 +525,14 @@ static socklen_t salen(const struct sockaddr *sa)
 		: sizeof(struct sockaddr_in);
 }
 
+/** True if @ss holds a v6-mapped-v4 address (RFC 4291, 2.5.5.2) */
+static bool SS_IS_ADDR_V4MAPPED(const struct sockaddr_storage *ss)
+{
+	const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
+
+	return ss->ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&ia6->sin6_addr);
+}
+
 /**
  * Process IPv4/v6 address, turn v6-mapped-v4 address into normal IPv4 address.
  * \param ss Container of IPv4/6 address.
@@ -531,11 +543,10 @@ static socklen_t salen(const struct sockaddr *sa)
 static const struct sockaddr *
 normalize_ip_address(const struct sockaddr_storage *ss)
 {
-	const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
-
 	assert(ss->ss_family == AF_INET || ss->ss_family == AF_INET6);
 
-	if (ss->ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&ia6->sin6_addr)) {
+	if (SS_IS_ADDR_V4MAPPED(ss)) {
+		const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
 		static struct sockaddr_in ia;
 
 		ia.sin_family = AF_INET;
@@ -546,30 +557,73 @@ normalize_ip_address(const struct sockaddr_storage *ss)
 	return (const struct sockaddr *)ss;
 }
 
+/**
+ * Generic/fallback MTU values
+ *
+ * These are taken from RFC 1122, RFC 2460, and RFC 5405.
+ * - RFC 1122, 3.3.3 defines EMTU_S ("Effective MTU for sending") and recommends
+ *   to use an EMTU_S size of of 576 bytes if the IPv4 path MTU is unknown;
+ * - RFC 2460, 5. requires a minimum IPv6 MTU of 1280 bytes;
+ * - RFC 5405, 3.2 recommends that if path MTU discovery is not done,
+ *   UDP senders should use the respective minimum values of EMTU_S.
+ */
+static inline int generic_mtu(const int af_type)
+{
+	return af_type == AF_INET6 ? 1280 : 576;
+}
+
+/** Crude approximation of IP header overhead - neglecting options. */
+static inline int estimated_header_overhead(const int af_type)
+{
+	return af_type == AF_INET6 ? 40 : 20;
+}
+
+/**
+ * Maximum transport-layer message size (MMS_S) as per RFC 1122, 3.3.3
+ * Socket must be connected.
+ */
+int generic_max_transport_msg_size(int sockfd)
+{
+	struct sockaddr_storage ss;
+	socklen_t sslen = sizeof(ss);
+	int af_type = AF_INET;
+
+	if (getpeername(sockfd, (struct sockaddr *)&ss, &sslen) < 0) {
+		PARA_ERROR_LOG("can not determine remote address type: %s\n",
+				strerror(errno));
+	} else if (!SS_IS_ADDR_V4MAPPED(&ss)) {
+		af_type = ss.ss_family;
+	}
+	return generic_mtu(af_type) - estimated_header_overhead(af_type);
+}
+
 /**
  * Print numeric host and port number (beware - uses static char).
  *
  * \param sa The IPv4/IPv6 socket address to use.
  *
+ * \return Host string in numeric host:port format, \sa parse_url().
  * \sa getnameinfo(3), services(5), nsswitch.conf(5)
  */
 static char *host_and_port(const struct sockaddr_storage *ss)
 {
 	const struct sockaddr *sa = normalize_ip_address(ss);
 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
-	static char output[sizeof(hbuf) + sizeof(sbuf) + 2];
+	static char output[sizeof(hbuf) + sizeof(sbuf) + 4];
 	int ret;
 
 	ret = getnameinfo(sa, salen(sa),
 			  hbuf, sizeof(hbuf),
 			  sbuf, sizeof(sbuf),
-			  NI_NUMERICHOST);
-	if (ret == 0) {
-		snprintf(output, sizeof(output), "%s#%s", hbuf, sbuf);
-	} else {
+			  NI_NUMERICHOST | NI_NUMERICSERV);
+	if (ret) {
 		snprintf(output, sizeof(output), "(unknown)");
 		PARA_WARNING_LOG("hostname lookup error (%s).\n",
 				 gai_strerror(ret));
+	} else if (sa->sa_family == AF_INET6) {
+		snprintf(output, sizeof(output), "[%s]:%s", hbuf, sbuf);
+	} else {
+		snprintf(output, sizeof(output), "%s:%s", hbuf, sbuf);
 	}
 	return output;
 }
@@ -756,23 +810,36 @@ int recv_buffer(int fd, char *buf, size_t size)
  * Wrapper around the accept system call.
  *
  * \param fd The listening socket.
+ * \param rfds An optional fd_set pointer.
  * \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 new_fd Result pointer.
  *
- * Accept incoming connections on \a addr. Retry if interrupted.
+ * Accept incoming connections on \a addr, retry if interrupted. If \a rfds is
+ * not \p NULL, return 0 if \a fd is not set in \a rfds without calling accept().
  *
- * \return The new file descriptor on success, negative on errors.
+ * \return Negative on errors, zero if no connections are present to be accepted,
+ * one otherwise.
  *
  * \sa accept(2).
  */
-int para_accept(int fd, void *addr, socklen_t size)
+int para_accept(int fd, fd_set *rfds, void *addr, socklen_t size, int *new_fd)
 {
-	int new_fd;
+	int ret;
 
+	if (rfds && !FD_ISSET(fd, rfds))
+		return 0;
 	do
-		new_fd = accept(fd, (struct sockaddr *) addr, &size);
-	while (new_fd < 0 && errno == EINTR);
-	return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
+		ret = accept(fd, (struct sockaddr *) addr, &size);
+	while (ret < 0 && errno == EINTR);
+
+	if (ret >= 0) {
+		*new_fd = ret;
+		return 1;
+	}
+	if (errno == EAGAIN || errno == EWOULDBLOCK)
+		return 0;
+	return -ERRNO_TO_PARA_ERROR(errno);
 }
 
 /**
@@ -878,15 +945,17 @@ err:
  * This function creates a local socket for sequenced, reliable, two-way,
  * connection-based byte streams.
  *
- * \return The file descriptor, on success, negative on errors.
+ * \return The file descriptor of the connected socket on success, negative on
+ * errors.
  *
  * \sa create_local_socket(), unix(7), connect(2).
  */
-int create_remote_socket(const char *name)
+int connect_local_socket(const char *name)
 {
 	struct sockaddr_un unix_addr;
 	int fd, ret;
 
+	PARA_DEBUG_LOG("connecting to %s\n", name);
 	ret = init_unix_addr(&unix_addr, name);
 	if (ret < 0)
 		return ret;
@@ -1017,41 +1086,3 @@ int recv_cred_buffer(int fd, char *buf, size_t size)
 	return result;
 }
 #endif /* HAVE_UCRED */
-
-/**
- * Receive a buffer and check for a pattern.
- *
- * \param fd The file descriptor to receive from.
- * \param pattern The expected pattern.
- * \param bufsize The size of the internal buffer.
- *
- * \return Positive if \a pattern was received, negative otherwise.
- *
- * 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).
- */
-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 + 1);
-
-	if (n < len)
-		goto out;
-	if (strncasecmp(buf, pattern, len))
-		goto out;
-	ret = 1;
-out:
-	if (ret < 0) {
-		PARA_NOTICE_LOG("did not receive pattern '%s'\n", pattern);
-		if (n > 0)
-			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;
-}