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-rw-r--r--src/proto_sockpair.c589
1 files changed, 589 insertions, 0 deletions
diff --git a/src/proto_sockpair.c b/src/proto_sockpair.c
new file mode 100644
index 0000000..a719063
--- /dev/null
+++ b/src/proto_sockpair.c
@@ -0,0 +1,589 @@
+/*
+ * Socket Pair protocol layer (sockpair)
+ *
+ * Copyright HAProxy Technologies - William Lallemand <wlallemand@haproxy.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <pwd.h>
+#include <grp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <time.h>
+
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+
+#include <haproxy/api.h>
+#include <haproxy/connection.h>
+#include <haproxy/errors.h>
+#include <haproxy/fd.h>
+#include <haproxy/freq_ctr.h>
+#include <haproxy/global.h>
+#include <haproxy/list.h>
+#include <haproxy/listener.h>
+#include <haproxy/log.h>
+#include <haproxy/protocol.h>
+#include <haproxy/proto_sockpair.h>
+#include <haproxy/sock.h>
+#include <haproxy/tools.h>
+#include <haproxy/version.h>
+
+
+static int sockpair_bind_listener(struct listener *listener, char *errmsg, int errlen);
+static void sockpair_enable_listener(struct listener *listener);
+static void sockpair_disable_listener(struct listener *listener);
+static int sockpair_connect_server(struct connection *conn, int flags);
+static int sockpair_accepting_conn(const struct receiver *rx);
+struct connection *sockpair_accept_conn(struct listener *l, int *status);
+
+struct proto_fam proto_fam_sockpair = {
+ .name = "sockpair",
+ .sock_domain = AF_CUST_SOCKPAIR,
+ .sock_family = AF_UNIX,
+ .sock_addrlen = sizeof(struct sockaddr_un),
+ .l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),
+ .addrcmp = NULL,
+ .bind = sockpair_bind_receiver,
+ .get_src = NULL,
+ .get_dst = NULL,
+};
+
+/* Note: must not be declared <const> as its list will be overwritten */
+struct protocol proto_sockpair = {
+ .name = "sockpair",
+
+ /* connection layer */
+ .xprt_type = PROTO_TYPE_STREAM,
+ .listen = sockpair_bind_listener,
+ .enable = sockpair_enable_listener,
+ .disable = sockpair_disable_listener,
+ .add = default_add_listener,
+ .unbind = default_unbind_listener,
+ .accept_conn = sockpair_accept_conn,
+ .ctrl_init = sock_conn_ctrl_init,
+ .ctrl_close = sock_conn_ctrl_close,
+ .connect = sockpair_connect_server,
+ .drain = sock_drain,
+ .check_events = sock_check_events,
+ .ignore_events = sock_ignore_events,
+
+ /* binding layer */
+ /* Note: suspend/resume not supported */
+
+ /* address family */
+ .fam = &proto_fam_sockpair,
+
+ /* socket layer */
+ .proto_type = PROTO_TYPE_STREAM,
+ .sock_type = SOCK_STREAM,
+ .sock_prot = 0,
+ .rx_enable = sock_enable,
+ .rx_disable = sock_disable,
+ .rx_unbind = sock_unbind,
+ .rx_listening = sockpair_accepting_conn,
+ .default_iocb = sock_accept_iocb,
+ .receivers = LIST_HEAD_INIT(proto_sockpair.receivers),
+ .nb_receivers = 0,
+};
+
+INITCALL1(STG_REGISTER, protocol_register, &proto_sockpair);
+
+/* Enable receipt of incoming connections for listener <l>. The receiver must
+ * still be valid.
+ */
+static void sockpair_enable_listener(struct listener *l)
+{
+ fd_want_recv_safe(l->rx.fd);
+}
+
+/* Disable receipt of incoming connections for listener <l>. The receiver must
+ * still be valid.
+ */
+static void sockpair_disable_listener(struct listener *l)
+{
+ fd_stop_recv(l->rx.fd);
+}
+
+/* Binds receiver <rx>, and assigns rx->iocb and rx->owner as the callback
+ * and context, respectively, with ->bind_thread as the thread mask. Returns an
+ * error code made of ERR_* bits on failure or ERR_NONE on success. On failure,
+ * an error message may be passed into <errmsg>. Note that the binding address
+ * is only an FD to receive the incoming FDs on. Thus by definition there is no
+ * real "bind" operation, this only completes the receiver. Such FDs are not
+ * inherited upon reload.
+ */
+int sockpair_bind_receiver(struct receiver *rx, char **errmsg)
+{
+ int err;
+
+ /* ensure we never return garbage */
+ if (errmsg)
+ *errmsg = 0;
+
+ err = ERR_NONE;
+
+ if (rx->flags & RX_F_BOUND)
+ return ERR_NONE;
+
+ if (rx->flags & RX_F_MUST_DUP) {
+ /* this is a secondary receiver that is an exact copy of a
+ * reference which must already be bound (or has failed).
+ * We'll try to dup() the other one's FD and take it. We
+ * try hard not to reconfigure the socket since it's shared.
+ */
+ BUG_ON(!rx->shard_info);
+ if (!(rx->shard_info->ref->flags & RX_F_BOUND)) {
+ /* it's assumed that the first one has already reported
+ * the error, let's not spam with another one, and do
+ * not set ERR_ALERT.
+ */
+ err |= ERR_RETRYABLE;
+ goto bind_ret_err;
+ }
+ /* taking the other one's FD will result in it being marked
+ * extern and being dup()ed. Let's mark the receiver as
+ * inherited so that it properly bypasses all second-stage
+ * setup and avoids being passed to new processes.
+ */
+ rx->flags |= RX_F_INHERITED;
+ rx->fd = rx->shard_info->ref->fd;
+ }
+
+ if (rx->fd == -1) {
+ err |= ERR_FATAL | ERR_ALERT;
+ memprintf(errmsg, "sockpair may be only used with inherited FDs");
+ goto bind_return;
+ }
+
+ if (rx->fd >= global.maxsock) {
+ err |= ERR_FATAL | ERR_ABORT | ERR_ALERT;
+ memprintf(errmsg, "not enough free sockets (raise '-n' parameter)");
+ goto bind_close_return;
+ }
+
+ if (fd_set_nonblock(rx->fd) == -1) {
+ err |= ERR_FATAL | ERR_ALERT;
+ memprintf(errmsg, "cannot make socket non-blocking");
+ goto bind_close_return;
+ }
+
+ rx->flags |= RX_F_BOUND;
+
+ fd_insert(rx->fd, rx->owner, rx->iocb, rx->bind_tgroup, rx->bind_thread);
+ return err;
+
+ bind_return:
+ if (errmsg && *errmsg)
+ memprintf(errmsg, "%s for [fd %d]", *errmsg, rx->fd);
+
+ bind_ret_err:
+ return err;
+
+ bind_close_return:
+ close(rx->fd);
+ goto bind_return;
+}
+
+/* This function changes the state from ASSIGNED to LISTEN. The socket is NOT
+ * enabled for polling. The return value is composed from ERR_NONE,
+ * ERR_RETRYABLE and ERR_FATAL. It may return a warning or an error message in
+ * <errmsg> if the message is at most <errlen> bytes long (including '\0').
+ * Note that <errmsg> may be NULL if <errlen> is also zero.
+ */
+static int sockpair_bind_listener(struct listener *listener, char *errmsg, int errlen)
+{
+ int err;
+ char *msg = NULL;
+
+ err = ERR_NONE;
+
+ /* ensure we never return garbage */
+ if (errlen)
+ *errmsg = 0;
+
+ if (listener->state != LI_ASSIGNED)
+ return ERR_NONE; /* already bound */
+
+ if (!(listener->rx.flags & RX_F_BOUND)) {
+ msg = "receiving socket not bound";
+ goto err_return;
+ }
+
+ listener_set_state(listener, LI_LISTEN);
+ return err;
+
+ err_return:
+ if (msg && errlen)
+ snprintf(errmsg, errlen, "%s [fd %d]", msg, listener->rx.fd);
+ return err;
+}
+
+/*
+ * Send FD over a unix socket
+ *
+ * <send_fd> is the FD to send
+ * <fd> is the fd of the unix socket to use for the transfer
+ *
+ * The iobuf variable could be use in the future to enhance the protocol.
+ */
+int send_fd_uxst(int fd, int send_fd)
+{
+ char iobuf[2];
+ struct iovec iov;
+ struct msghdr msghdr;
+
+ char cmsgbuf[CMSG_SPACE(sizeof(int))];
+ char buf[CMSG_SPACE(sizeof(int))];
+ struct cmsghdr *cmsg = (void *)buf;
+
+ int *fdptr;
+
+ iov.iov_base = iobuf;
+ iov.iov_len = sizeof(iobuf);
+
+ memset(&msghdr, 0, sizeof(msghdr));
+ msghdr.msg_iov = &iov;
+ msghdr.msg_iovlen = 1;
+
+ /* Now send the fds */
+ msghdr.msg_control = cmsgbuf;
+ msghdr.msg_controllen = CMSG_SPACE(sizeof(int));
+
+ cmsg = CMSG_FIRSTHDR(&msghdr);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+
+ fdptr = (int *)CMSG_DATA(cmsg);
+ memcpy(fdptr, &send_fd, sizeof(send_fd));
+
+ if (sendmsg(fd, &msghdr, 0) != sizeof(iobuf)) {
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ *
+ * This function works like uxst_connect_server but instead of creating a
+ * socket and establishing a connection, it creates a pair of connected
+ * sockets, and send one of them through the destination FD. The destination FD
+ * is stored in conn->dst->sin_addr.s_addr during configuration parsing.
+ *
+ * conn->target may point either to a valid server or to a backend, depending
+ * on conn->target. Only OBJ_TYPE_PROXY and OBJ_TYPE_SERVER are supported. The
+ * <data> parameter is a boolean indicating whether there are data waiting for
+ * being sent or not, in order to adjust data write polling and on some
+ * platforms. The <delack> argument is ignored.
+ *
+ * Note that a pending send_proxy message accounts for data.
+ *
+ * It can return one of :
+ * - SF_ERR_NONE if everything's OK
+ * - SF_ERR_SRVTO if there are no more servers
+ * - SF_ERR_SRVCL if the connection was refused by the server
+ * - SF_ERR_PRXCOND if the connection has been limited by the proxy (maxconn)
+ * - SF_ERR_RESOURCE if a system resource is lacking (eg: fd limits, ports, ...)
+ * - SF_ERR_INTERNAL for any other purely internal errors
+ * Additionally, in the case of SF_ERR_RESOURCE, an emergency log will be emitted.
+ *
+ * The connection's fd is inserted only when SF_ERR_NONE is returned, otherwise
+ * it's invalid and the caller has nothing to do.
+ */
+static int sockpair_connect_server(struct connection *conn, int flags)
+{
+ int sv[2], fd, dst_fd = -1;
+
+ BUG_ON(!conn->dst);
+
+ /* the FD is stored in the sockaddr struct */
+ dst_fd = ((struct sockaddr_in *)conn->dst)->sin_addr.s_addr;
+
+ if (obj_type(conn->target) != OBJ_TYPE_PROXY &&
+ obj_type(conn->target) != OBJ_TYPE_SERVER) {
+ conn->flags |= CO_FL_ERROR;
+ return SF_ERR_INTERNAL;
+ }
+
+ if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
+ ha_alert("socketpair(): Cannot create socketpair. Giving up.\n");
+ conn->flags |= CO_FL_ERROR;
+ return SF_ERR_RESOURCE;
+ }
+
+ fd = conn->handle.fd = sv[1];
+
+ if (fd >= global.maxsock) {
+ /* do not log anything there, it's a normal condition when this option
+ * is used to serialize connections to a server !
+ */
+ ha_alert("socket(): not enough free sockets. Raise -n argument. Giving up.\n");
+ close(sv[0]);
+ close(sv[1]);
+ conn->err_code = CO_ER_CONF_FDLIM;
+ conn->flags |= CO_FL_ERROR;
+ return SF_ERR_PRXCOND; /* it is a configuration limit */
+ }
+
+ if (fd_set_nonblock(fd) == -1) {
+ qfprintf(stderr,"Cannot set client socket to non blocking mode.\n");
+ close(sv[0]);
+ close(sv[1]);
+ conn->err_code = CO_ER_SOCK_ERR;
+ conn->flags |= CO_FL_ERROR;
+ return SF_ERR_INTERNAL;
+ }
+
+ if (master == 1 && fd_set_cloexec(fd) == -1) {
+ ha_alert("Cannot set CLOEXEC on client socket.\n");
+ close(sv[0]);
+ close(sv[1]);
+ conn->err_code = CO_ER_SOCK_ERR;
+ conn->flags |= CO_FL_ERROR;
+ return SF_ERR_INTERNAL;
+ }
+
+ if (global.tune.server_sndbuf)
+ setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &global.tune.server_sndbuf, sizeof(global.tune.server_sndbuf));
+
+ if (global.tune.server_rcvbuf)
+ setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &global.tune.server_rcvbuf, sizeof(global.tune.server_rcvbuf));
+
+ /* The new socket is sent on the other side, it should be retrieved and
+ * considered as an 'accept' socket on the server side */
+ if (send_fd_uxst(dst_fd, sv[0]) == -1) {
+ ha_alert("socketpair: Cannot transfer the fd %d over sockpair@%d. Giving up.\n", sv[0], dst_fd);
+ close(sv[0]);
+ close(sv[1]);
+ conn->err_code = CO_ER_SOCK_ERR;
+ conn->flags |= CO_FL_ERROR;
+ return SF_ERR_INTERNAL;
+ }
+
+ close(sv[0]); /* we don't need this side anymore */
+
+ conn->flags &= ~CO_FL_WAIT_L4_CONN;
+
+ /* Prepare to send a few handshakes related to the on-wire protocol. */
+ if (conn->send_proxy_ofs)
+ conn->flags |= CO_FL_SEND_PROXY;
+
+ conn_ctrl_init(conn); /* registers the FD */
+ HA_ATOMIC_AND(&fdtab[fd].state, ~FD_LINGER_RISK); /* no need to disable lingering */
+
+ return SF_ERR_NONE; /* connection is OK */
+}
+
+
+/*
+ * Receives a file descriptor transferred from a unix socket.
+ *
+ * Return -1 or a socket fd;
+ *
+ * The iobuf variable could be used in the future to enhance the protocol.
+ */
+int recv_fd_uxst(int sock)
+{
+ struct msghdr msghdr;
+ struct iovec iov;
+ char iobuf[2];
+
+ char cmsgbuf[CMSG_SPACE(sizeof(int))];
+ char buf[CMSG_SPACE(sizeof(int))];
+ struct cmsghdr *cmsg = (void *)buf;
+
+
+ int recv_fd = -1;
+ int ret = -1;
+
+ memset(&msghdr, 0, sizeof(msghdr));
+
+ iov.iov_base = iobuf;
+ iov.iov_len = sizeof(iobuf);
+
+ msghdr.msg_iov = &iov;
+ msghdr.msg_iovlen = 1;
+
+ msghdr.msg_control = cmsgbuf;
+ msghdr.msg_controllen = CMSG_SPACE(sizeof(int));
+
+ iov.iov_len = sizeof(iobuf);
+ iov.iov_base = iobuf;
+
+ while (1) {
+ ret = recvmsg(sock, &msghdr, 0);
+ if (ret == -1 && errno == EINTR)
+ continue;
+ else
+ break;
+ }
+
+ if (ret == -1)
+ return ret;
+
+ cmsg = CMSG_FIRSTHDR(&msghdr);
+ if (cmsg && cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_RIGHTS) {
+ size_t totlen = cmsg->cmsg_len -
+ CMSG_LEN(0);
+ memcpy(&recv_fd, CMSG_DATA(cmsg), totlen);
+ }
+ return recv_fd;
+}
+
+/* Tests if the receiver supports accepting connections. Returns positive on
+ * success, 0 if not possible, negative if the socket is non-recoverable. In
+ * practice zero is never returned since we don't support suspending sockets.
+ * The real test consists in verifying we have a connected SOCK_STREAM of
+ * family AF_UNIX.
+ */
+static int sockpair_accepting_conn(const struct receiver *rx)
+{
+ struct sockaddr sa;
+ socklen_t len;
+ int val;
+
+ len = sizeof(val);
+ if (getsockopt(rx->fd, SOL_SOCKET, SO_TYPE, &val, &len) == -1)
+ return -1;
+
+ if (val != SOCK_STREAM)
+ return -1;
+
+ len = sizeof(sa);
+ if (getsockname(rx->fd, &sa, &len) != 0)
+ return -1;
+
+ if (sa.sa_family != AF_UNIX)
+ return -1;
+
+ len = sizeof(val);
+ if (getsockopt(rx->fd, SOL_SOCKET, SO_ACCEPTCONN, &val, &len) == -1)
+ return -1;
+
+ /* Note: cannot be a listening socket, must be established */
+ if (val)
+ return -1;
+
+ return 1;
+}
+
+/* Accept an incoming connection from listener <l>, and return it, as well as
+ * a CO_AC_* status code into <status> if not null. Null is returned on error.
+ * <l> must be a valid listener with a valid frontend.
+ */
+struct connection *sockpair_accept_conn(struct listener *l, int *status)
+{
+ struct proxy *p = l->bind_conf->frontend;
+ struct connection *conn = NULL;
+ int ret;
+ int cfd;
+
+ if ((cfd = recv_fd_uxst(l->rx.fd)) != -1)
+ fd_set_nonblock(cfd);
+
+ if (likely(cfd != -1)) {
+ /* Perfect, the connection was accepted */
+ conn = conn_new(&l->obj_type);
+ if (!conn)
+ goto fail_conn;
+
+ if (!sockaddr_alloc(&conn->src, NULL, 0))
+ goto fail_addr;
+
+ /* just like with UNIX sockets, only the family is filled */
+ conn->src->ss_family = AF_UNIX;
+ conn->handle.fd = cfd;
+ ret = CO_AC_DONE;
+ goto done;
+ }
+
+ switch (errno) {
+#if defined(EWOULDBLOCK) && defined(EAGAIN) && EWOULDBLOCK != EAGAIN
+ case EWOULDBLOCK:
+#endif
+ case EAGAIN:
+ ret = CO_AC_DONE; /* nothing more to accept */
+ if (fdtab[l->rx.fd].state & (FD_POLL_HUP|FD_POLL_ERR)) {
+ /* the listening socket might have been disabled in a shared
+ * process and we're a collateral victim. We'll just pause for
+ * a while in case it comes back. In the mean time, we need to
+ * clear this sticky flag.
+ */
+ _HA_ATOMIC_AND(&fdtab[l->rx.fd].state, ~(FD_POLL_HUP|FD_POLL_ERR));
+ ret = CO_AC_PAUSE;
+ }
+ fd_cant_recv(l->rx.fd);
+ break;
+
+ case EINVAL:
+ /* might be trying to accept on a shut fd (eg: soft stop) */
+ ret = CO_AC_PAUSE;
+ break;
+
+ case EINTR:
+ case ECONNABORTED:
+ ret = CO_AC_RETRY;
+ break;
+
+ case ENFILE:
+ if (p)
+ send_log(p, LOG_EMERG,
+ "Proxy %s reached system FD limit (maxsock=%d). Please check system tunables.\n",
+ p->id, global.maxsock);
+ ret = CO_AC_PAUSE;
+ break;
+
+ case EMFILE:
+ if (p)
+ send_log(p, LOG_EMERG,
+ "Proxy %s reached process FD limit (maxsock=%d). Please check 'ulimit-n' and restart.\n",
+ p->id, global.maxsock);
+ ret = CO_AC_PAUSE;
+ break;
+
+ case ENOBUFS:
+ case ENOMEM:
+ if (p)
+ send_log(p, LOG_EMERG,
+ "Proxy %s reached system memory limit (maxsock=%d). Please check system tunables.\n",
+ p->id, global.maxsock);
+ ret = CO_AC_PAUSE;
+ break;
+
+ default:
+ /* unexpected result, let's give up and let other tasks run */
+ ret = CO_AC_YIELD;
+ }
+ done:
+ if (status)
+ *status = ret;
+ return conn;
+
+ fail_addr:
+ conn_free(conn);
+ conn = NULL;
+ fail_conn:
+ ret = CO_AC_PAUSE;
+ goto done;
+}
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */
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