diff options
Diffstat (limited to 'src/proto_sockpair.c')
-rw-r--r-- | src/proto_sockpair.c | 564 |
1 files changed, 564 insertions, 0 deletions
diff --git a/src/proto_sockpair.c b/src/proto_sockpair.c new file mode 100644 index 0000000..e140fda --- /dev/null +++ b/src/proto_sockpair.c @@ -0,0 +1,564 @@ +/* + * 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->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, thread_mask(rx->bind_thread) & all_threads_mask); + return err; + + bind_return: + if (errmsg && *errmsg) + memprintf(errmsg, "%s for [fd %d]", *errmsg, rx->fd); + + 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)) { + ha_warning("Failed to transfer socket\n"); + 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) { + 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: + */ |