src/connection.c

/*
 * Connection management functions
 *
 * Copyright 2000-2012 Willy Tarreau <w@1wt.eu>
 *
 * 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 <errno.h>

#include <common/compat.h>
#include <common/config.h>
#include <common/initcall.h>
#include <common/namespace.h>
#include <common/hash.h>
#include <common/net_helper.h>

#include <proto/connection.h>
#include <proto/fd.h>
#include <proto/frontend.h>
#include <proto/proto_tcp.h>
#include <proto/stream_interface.h>
#include <proto/sample.h>
#include <proto/ssl_sock.h>

#include <common/debug.h>

DECLARE_POOL(pool_head_connection, "connection",  sizeof(struct connection));
DECLARE_POOL(pool_head_connstream, "conn_stream", sizeof(struct conn_stream));
DECLARE_POOL(pool_head_sockaddr,   "sockaddr",    sizeof(struct sockaddr_storage));
DECLARE_POOL(pool_head_authority,  "authority",   PP2_AUTHORITY_MAX);

struct xprt_ops *registered_xprt[XPRT_ENTRIES] = { NULL, };

/* List head of all known muxes for PROTO */
struct mux_proto_list mux_proto_list = {
        .list = LIST_HEAD_INIT(mux_proto_list.list)
};

int conn_create_mux(struct connection *conn)
{
	if (conn_is_back(conn)) {
		struct server *srv;
		struct conn_stream *cs = conn->ctx;

		if (conn->flags & CO_FL_ERROR)
			goto fail;

		if (conn_install_mux_be(conn, conn->ctx, conn->owner) < 0)
			goto fail;
		srv = objt_server(conn->target);
		if (srv && ((srv->proxy->options & PR_O_REUSE_MASK) != PR_O_REUSE_NEVR) &&
		    conn->mux->avail_streams(conn) > 0)
			LIST_ADD(&srv->idle_conns[tid], &conn->list);
		return 0;
fail:
		/* let the upper layer know the connection failed */
		cs->data_cb->wake(cs);
		return -1;
	} else
		return conn_complete_session(conn);

}

/* I/O callback for fd-based connections. It calls the read/write handlers
 * provided by the connection's sock_ops, which must be valid.
 */
void conn_fd_handler(int fd)
{
	struct connection *conn = fdtab[fd].owner;
	unsigned int flags;
	int io_available = 0;

	if (unlikely(!conn)) {
		activity[tid].conn_dead++;
		return;
	}

	flags = conn->flags & ~CO_FL_ERROR; /* ensure to call the wake handler upon error */

	if (unlikely(conn->flags & CO_FL_WAIT_L4_CONN) &&
	    ((fd_send_ready(fd) && fd_send_active(fd)) ||
	     (fd_recv_ready(fd) && fd_recv_active(fd)))) {
		/* Still waiting for a connection to establish and nothing was
		 * attempted yet to probe the connection. this will clear the
		 * CO_FL_WAIT_L4_CONN flag on success.
		 */
		if (!conn_fd_check(conn))
			goto leave;
	}

	if (fd_send_ready(fd) && fd_send_active(fd)) {
		/* force reporting of activity by clearing the previous flags :
		 * we'll have at least ERROR or CONNECTED at the end of an I/O,
		 * both of which will be detected below.
		 */
		flags = 0;
		if (conn->subs && conn->subs->events & SUB_RETRY_SEND) {
			tasklet_wakeup(conn->subs->tasklet);
			conn->subs->events &= ~SUB_RETRY_SEND;
			if (!conn->subs->events)
				conn->subs = NULL;
		} else
			io_available = 1;
		__conn_xprt_stop_send(conn);
	}

	/* The data transfer starts here and stops on error and handshakes. Note
	 * that we must absolutely test conn->xprt at each step in case it suddenly
	 * changes due to a quick unexpected close().
	 */
	if (fd_recv_ready(fd) && fd_recv_active(fd)) {
		/* force reporting of activity by clearing the previous flags :
		 * we'll have at least ERROR or CONNECTED at the end of an I/O,
		 * both of which will be detected below.
		 */
		flags = 0;
		if (conn->subs && conn->subs->events & SUB_RETRY_RECV) {
			tasklet_wakeup(conn->subs->tasklet);
			conn->subs->events &= ~SUB_RETRY_RECV;
			if (!conn->subs->events)
				conn->subs = NULL;
		} else
			io_available = 1;
		__conn_xprt_stop_recv(conn);
	}

 leave:
	/* If we don't yet have a mux, that means we were waiting for
	 * informations to create one, typically from the ALPN. If we're
	 * done with the handshake, attempt to create one.
	 */
	if (unlikely(!conn->mux) && !(conn->flags & CO_FL_WAIT_XPRT))
		if (conn_create_mux(conn) < 0)
			return;

	/* The wake callback is normally used to notify the data layer about
	 * data layer activity (successful send/recv), connection establishment,
	 * shutdown and fatal errors. We need to consider the following
	 * situations to wake up the data layer :
	 *  - change among the CO_FL_NOTIFY_DONE flags :
	 *      SOCK_{RD,WR}_SH, ERROR,
	 *  - absence of any of {L4,L6}_CONN and CONNECTED, indicating the
	 *    end of handshake and transition to CONNECTED
	 *  - raise of CONNECTED with HANDSHAKE down
	 *  - end of HANDSHAKE with CONNECTED set
	 *  - regular data layer activity
	 *
	 * Note that the wake callback is allowed to release the connection and
	 * the fd (and return < 0 in this case).
	 */
	if ((io_available || ((conn->flags ^ flags) & CO_FL_NOTIFY_DONE) ||
	     ((flags & CO_FL_WAIT_XPRT) && !(conn->flags & CO_FL_WAIT_XPRT))) &&
	    conn->mux && conn->mux->wake && conn->mux->wake(conn) < 0)
		return;

	/* commit polling changes */
	conn_cond_update_polling(conn);
	return;
}

/* This is the callback which is set when a connection establishment is pending
 * and we have nothing to send. It may update the FD polling status to indicate
 * !READY. It returns 0 if it fails in a fatal way or needs to poll to go
 * further, otherwise it returns non-zero and removes the CO_FL_WAIT_L4_CONN
 * flag from the connection's flags. In case of error, it sets CO_FL_ERROR and
 * leaves the error code in errno.
 */
int conn_fd_check(struct connection *conn)
{
	struct sockaddr_storage *addr;
	int fd = conn->handle.fd;

	if (conn->flags & CO_FL_ERROR)
		return 0;

	if (!conn_ctrl_ready(conn))
		return 0;

	if (!(conn->flags & CO_FL_WAIT_L4_CONN))
		return 1; /* strange we were called while ready */

	if (!fd_send_ready(fd))
		return 0;

	/* Here we have 2 cases :
	 *  - modern pollers, able to report ERR/HUP. If these ones return any
	 *    of these flags then it's likely a failure, otherwise it possibly
	 *    is a success (i.e. there may have been data received just before
	 *    the error was reported).
	 *  - select, which doesn't report these and with which it's always
	 *    necessary either to try connect() again or to check for SO_ERROR.
	 * In order to simplify everything, we double-check using connect() as
	 * soon as we meet either of these delicate situations. Note that
	 * SO_ERROR would clear the error after reporting it!
	 */
	if (cur_poller.flags & HAP_POLL_F_ERRHUP) {
		/* modern poller, able to report ERR/HUP */
		if ((fdtab[fd].ev & (FD_POLL_IN|FD_POLL_ERR|FD_POLL_HUP)) == FD_POLL_IN)
			goto done;
		if ((fdtab[fd].ev & (FD_POLL_OUT|FD_POLL_ERR|FD_POLL_HUP)) == FD_POLL_OUT)
			goto done;
		if (!(fdtab[fd].ev & (FD_POLL_ERR|FD_POLL_HUP)))
			goto wait;
		/* error present, fall through common error check path */
	}

	/* Use connect() to check the state of the socket. This has the double
	 * advantage of *not* clearing the error (so that health checks can
	 * still use getsockopt(SO_ERROR)) and giving us the following info :
	 *  - error
	 *  - connecting (EALREADY, EINPROGRESS)
	 *  - connected (EISCONN, 0)
	 */
	addr = conn->dst;
	if ((conn->flags & CO_FL_SOCKS4) && obj_type(conn->target) == OBJ_TYPE_SERVER)
		addr = &objt_server(conn->target)->socks4_addr;

	if (connect(fd, (const struct sockaddr *)addr, get_addr_len(addr)) == -1) {
		if (errno == EALREADY || errno == EINPROGRESS)
			goto wait;

		if (errno && errno != EISCONN)
			goto out_error;
	}

 done:
	/* The FD is ready now, we'll mark the connection as complete and
	 * forward the event to the transport layer which will notify the
	 * data layer.
	 */
	conn->flags &= ~CO_FL_WAIT_L4_CONN;
	fd_may_send(fd);
	fd_cond_recv(fd);
	errno = 0; // make health checks happy
	return 1;

 out_error:
	/* Write error on the file descriptor. Report it to the connection
	 * and disable polling on this FD.
	 */
	fdtab[fd].linger_risk = 0;
	conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
	__conn_xprt_stop_both(conn);
	return 0;

 wait:
	__conn_xprt_want_send(conn);
	fd_cant_send(fd);
	return 0;
}

/* Send a message over an established connection. It makes use of send() and
 * returns the same return code and errno. If the socket layer is not ready yet
 * then -1 is returned and ENOTSOCK is set into errno. If the fd is not marked
 * as ready, or if EAGAIN or ENOTCONN is returned, then we return 0. It returns
 * EMSGSIZE if called with a zero length message. The purpose is to simplify
 * some rare attempts to directly write on the socket from above the connection
 * (typically send_proxy). In case of EAGAIN, the fd is marked as "cant_send".
 * It automatically retries on EINTR. Other errors cause the connection to be
 * marked as in error state. It takes similar arguments as send() except the
 * first one which is the connection instead of the file descriptor. Note,
 * MSG_DONTWAIT and MSG_NOSIGNAL are forced on the flags.
 */
int conn_sock_send(struct connection *conn, const void *buf, int len, int flags)
{
	int ret;

	ret = -1;
	errno = ENOTSOCK;

	if (conn->flags & CO_FL_SOCK_WR_SH)
		goto fail;

	if (!conn_ctrl_ready(conn))
		goto fail;

	errno = EMSGSIZE;
	if (!len)
		goto fail;

	if (!fd_send_ready(conn->handle.fd))
		goto wait;

	do {
		ret = send(conn->handle.fd, buf, len, flags | MSG_DONTWAIT | MSG_NOSIGNAL);
	} while (ret < 0 && errno == EINTR);


	if (ret > 0) {
		if (conn->flags & CO_FL_WAIT_L4_CONN) {
			conn->flags &= ~CO_FL_WAIT_L4_CONN;
			fd_may_send(conn->handle.fd);
			fd_cond_recv(conn->handle.fd);
		}
		return ret;
	}

	if (ret == 0 || errno == EAGAIN || errno == ENOTCONN) {
	wait:
		fd_cant_send(conn->handle.fd);
		return 0;
	}
 fail:
	conn->flags |= CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH | CO_FL_ERROR;
	return ret;
}

/* Called from the upper layer, to subscribe <es> to events <event_type>. The
 * event subscriber <es> is not allowed to change from a previous call as long
 * as at least one event is still subscribed. The <event_type> must only be a
 * combination of SUB_RETRY_RECV and SUB_RETRY_SEND. It always returns 0.
 */
int conn_unsubscribe(struct connection *conn, void *xprt_ctx, int event_type, struct wait_event *es)
{
	BUG_ON(event_type & ~(SUB_RETRY_SEND|SUB_RETRY_RECV));
	BUG_ON(conn->subs && conn->subs != es);

	es->events &= ~event_type;
	if (!es->events)
		conn->subs = NULL;

	if (event_type & SUB_RETRY_RECV)
		__conn_xprt_stop_recv(conn);

	if (event_type & SUB_RETRY_SEND)
		__conn_xprt_stop_send(conn);

	return 0;
}

/* Called from the upper layer, to unsubscribe <es> from events <event_type>
 * (undo fcgi_subscribe). The <es> struct is not allowed to differ from the one
 * passed to the subscribe() call. It always returns zero.
 */
int conn_subscribe(struct connection *conn, void *xprt_ctx, int event_type, struct wait_event *es)
{
	BUG_ON(event_type & ~(SUB_RETRY_SEND|SUB_RETRY_RECV));
	BUG_ON(conn->subs && conn->subs->events & event_type);
	BUG_ON(conn->subs && conn->subs != es);

	conn->subs = es;
	es->events |= event_type;

	if (event_type & SUB_RETRY_RECV)
		__conn_xprt_want_recv(conn);

	if (event_type & SUB_RETRY_SEND)
		__conn_xprt_want_send(conn);

	return 0;
}

/* Drains possibly pending incoming data on the file descriptor attached to the
 * connection and update the connection's flags accordingly. This is used to
 * know whether we need to disable lingering on close. Returns non-zero if it
 * is safe to close without disabling lingering, otherwise zero. The SOCK_RD_SH
 * flag may also be updated if the incoming shutdown was reported by the drain()
 * function.
 */
int conn_sock_drain(struct connection *conn)
{
	int turns = 2;
	int len;

	if (!conn_ctrl_ready(conn))
		return 1;

	if (conn->flags & (CO_FL_ERROR | CO_FL_SOCK_RD_SH))
		return 1;

	if (fdtab[conn->handle.fd].ev & (FD_POLL_ERR|FD_POLL_HUP))
		goto shut;

	if (!fd_recv_ready(conn->handle.fd))
		return 0;

	if (conn->ctrl->drain) {
		if (conn->ctrl->drain(conn->handle.fd) <= 0)
			return 0;
		goto shut;
	}

	/* no drain function defined, use the generic one */

	while (turns) {
#ifdef MSG_TRUNC_CLEARS_INPUT
		len = recv(conn->handle.fd, NULL, INT_MAX, MSG_DONTWAIT | MSG_NOSIGNAL | MSG_TRUNC);
		if (len == -1 && errno == EFAULT)
#endif
			len = recv(conn->handle.fd, trash.area, trash.size,
				   MSG_DONTWAIT | MSG_NOSIGNAL);

		if (len == 0)
			goto shut;

		if (len < 0) {
			if (errno == EAGAIN) {
				/* connection not closed yet */
				fd_cant_recv(conn->handle.fd);
				break;
			}
			if (errno == EINTR)  /* oops, try again */
				continue;
			/* other errors indicate a dead connection, fine. */
			goto shut;
		}
		/* OK we read some data, let's try again once */
		turns--;
	}

	/* some data are still present, give up */
	return 0;

 shut:
	/* we're certain the connection was shut down */
	fdtab[conn->handle.fd].linger_risk = 0;
	conn->flags |= CO_FL_SOCK_RD_SH;
	return 1;
}

/*
 * Get data length from tlv
 */
static int get_tlv_length(const struct tlv *src)
{
	return (src->length_hi << 8) | src->length_lo;
}

/* This handshake handler waits a PROXY protocol header at the beginning of the
 * raw data stream. The header looks like this :
 *
 *   "PROXY" <SP> PROTO <SP> SRC3 <SP> DST3 <SP> SRC4 <SP> <DST4> "\r\n"
 *
 * There must be exactly one space between each field. Fields are :
 *  - PROTO : layer 4 protocol, which must be "TCP4" or "TCP6".
 *  - SRC3  : layer 3 (eg: IP) source address in standard text form
 *  - DST3  : layer 3 (eg: IP) destination address in standard text form
 *  - SRC4  : layer 4 (eg: TCP port) source address in standard text form
 *  - DST4  : layer 4 (eg: TCP port) destination address in standard text form
 *
 * This line MUST be at the beginning of the buffer and MUST NOT wrap.
 *
 * The header line is small and in all cases smaller than the smallest normal
 * TCP MSS. So it MUST always be delivered as one segment, which ensures we
 * can safely use MSG_PEEK and avoid buffering.
 *
 * Once the data is fetched, the values are set in the connection's address
 * fields, and data are removed from the socket's buffer. The function returns
 * zero if it needs to wait for more data or if it fails, or 1 if it completed
 * and removed itself.
 */
int conn_recv_proxy(struct connection *conn, int flag)
{
	char *line, *end;
	struct proxy_hdr_v2 *hdr_v2;
	const char v2sig[] = PP2_SIGNATURE;
	int tlv_length = 0;
	int tlv_offset = 0;
	int ret;

	if (!conn_ctrl_ready(conn))
		goto fail;

	if (!sockaddr_alloc(&conn->src) || !sockaddr_alloc(&conn->dst))
		goto fail;

	if (!fd_recv_ready(conn->handle.fd))
		goto not_ready;

	while (1) {
		ret = recv(conn->handle.fd, trash.area, trash.size, MSG_PEEK);
		if (ret < 0) {
			if (errno == EINTR)
				continue;
			if (errno == EAGAIN) {
				fd_cant_recv(conn->handle.fd);
				goto not_ready;
			}
			goto recv_abort;
		}
		trash.data = ret;
		break;
	}

	if (!trash.data) {
		/* client shutdown */
		conn->err_code = CO_ER_PRX_EMPTY;
		goto fail;
	}

	conn->flags &= ~CO_FL_WAIT_L4_CONN;

	if (trash.data < 6)
		goto missing;

	line = trash.area;
	end = trash.area + trash.data;

	/* Decode a possible proxy request, fail early if it does not match */
	if (strncmp(line, "PROXY ", 6) != 0)
		goto not_v1;

	line += 6;
	if (trash.data < 9) /* shortest possible line */
		goto missing;

	if (memcmp(line, "TCP4 ", 5) == 0) {
		u32 src3, dst3, sport, dport;

		line += 5;

		src3 = inetaddr_host_lim_ret(line, end, &line);
		if (line == end)
			goto missing;
		if (*line++ != ' ')
			goto bad_header;

		dst3 = inetaddr_host_lim_ret(line, end, &line);
		if (line == end)
			goto missing;
		if (*line++ != ' ')
			goto bad_header;

		sport = read_uint((const char **)&line, end);
		if (line == end)
			goto missing;
		if (*line++ != ' ')
			goto bad_header;

		dport = read_uint((const char **)&line, end);
		if (line > end - 2)
			goto missing;
		if (*line++ != '\r')
			goto bad_header;
		if (*line++ != '\n')
			goto bad_header;

		/* update the session's addresses and mark them set */
		((struct sockaddr_in *)conn->src)->sin_family      = AF_INET;
		((struct sockaddr_in *)conn->src)->sin_addr.s_addr = htonl(src3);
		((struct sockaddr_in *)conn->src)->sin_port        = htons(sport);

		((struct sockaddr_in *)conn->dst)->sin_family        = AF_INET;
		((struct sockaddr_in *)conn->dst)->sin_addr.s_addr   = htonl(dst3);
		((struct sockaddr_in *)conn->dst)->sin_port          = htons(dport);
		conn->flags |= CO_FL_ADDR_FROM_SET | CO_FL_ADDR_TO_SET;
	}
	else if (memcmp(line, "TCP6 ", 5) == 0) {
		u32 sport, dport;
		char *src_s;
		char *dst_s, *sport_s, *dport_s;
		struct in6_addr src3, dst3;

		line += 5;

		src_s = line;
		dst_s = sport_s = dport_s = NULL;
		while (1) {
			if (line > end - 2) {
				goto missing;
			}
			else if (*line == '\r') {
				*line = 0;
				line++;
				if (*line++ != '\n')
					goto bad_header;
				break;
			}

			if (*line == ' ') {
				*line = 0;
				if (!dst_s)
					dst_s = line + 1;
				else if (!sport_s)
					sport_s = line + 1;
				else if (!dport_s)
					dport_s = line + 1;
			}
			line++;
		}

		if (!dst_s || !sport_s || !dport_s)
			goto bad_header;

		sport = read_uint((const char **)&sport_s,dport_s - 1);
		if (*sport_s != 0)
			goto bad_header;

		dport = read_uint((const char **)&dport_s,line - 2);
		if (*dport_s != 0)
			goto bad_header;

		if (inet_pton(AF_INET6, src_s, (void *)&src3) != 1)
			goto bad_header;

		if (inet_pton(AF_INET6, dst_s, (void *)&dst3) != 1)
			goto bad_header;

		/* update the session's addresses and mark them set */
		((struct sockaddr_in6 *)conn->src)->sin6_family      = AF_INET6;
		memcpy(&((struct sockaddr_in6 *)conn->src)->sin6_addr, &src3, sizeof(struct in6_addr));
		((struct sockaddr_in6 *)conn->src)->sin6_port        = htons(sport);

		((struct sockaddr_in6 *)conn->dst)->sin6_family        = AF_INET6;
		memcpy(&((struct sockaddr_in6 *)conn->dst)->sin6_addr, &dst3, sizeof(struct in6_addr));
		((struct sockaddr_in6 *)conn->dst)->sin6_port          = htons(dport);
		conn->flags |= CO_FL_ADDR_FROM_SET | CO_FL_ADDR_TO_SET;
	}
	else if (memcmp(line, "UNKNOWN\r\n", 9) == 0) {
		/* This can be a UNIX socket forwarded by an haproxy upstream */
		line += 9;
	}
	else {
		/* The protocol does not match something known (TCP4/TCP6/UNKNOWN) */
		conn->err_code = CO_ER_PRX_BAD_PROTO;
		goto fail;
	}

	trash.data = line - trash.area;
	goto eat_header;

 not_v1:
	/* try PPv2 */
	if (trash.data < PP2_HEADER_LEN)
		goto missing;

	hdr_v2 = (struct proxy_hdr_v2 *) trash.area;

	if (memcmp(hdr_v2->sig, v2sig, PP2_SIGNATURE_LEN) != 0 ||
	    (hdr_v2->ver_cmd & PP2_VERSION_MASK) != PP2_VERSION) {
		conn->err_code = CO_ER_PRX_NOT_HDR;
		goto fail;
	}

	if (trash.data < PP2_HEADER_LEN + ntohs(hdr_v2->len))
		goto missing;

	switch (hdr_v2->ver_cmd & PP2_CMD_MASK) {
	case 0x01: /* PROXY command */
		switch (hdr_v2->fam) {
		case 0x11:  /* TCPv4 */
			if (ntohs(hdr_v2->len) < PP2_ADDR_LEN_INET)
				goto bad_header;

			((struct sockaddr_in *)conn->src)->sin_family = AF_INET;
			((struct sockaddr_in *)conn->src)->sin_addr.s_addr = hdr_v2->addr.ip4.src_addr;
			((struct sockaddr_in *)conn->src)->sin_port = hdr_v2->addr.ip4.src_port;
			((struct sockaddr_in *)conn->dst)->sin_family = AF_INET;
			((struct sockaddr_in *)conn->dst)->sin_addr.s_addr = hdr_v2->addr.ip4.dst_addr;
			((struct sockaddr_in *)conn->dst)->sin_port = hdr_v2->addr.ip4.dst_port;
			conn->flags |= CO_FL_ADDR_FROM_SET | CO_FL_ADDR_TO_SET;
			tlv_offset = PP2_HEADER_LEN + PP2_ADDR_LEN_INET;
			tlv_length = ntohs(hdr_v2->len) - PP2_ADDR_LEN_INET;
			break;
		case 0x21:  /* TCPv6 */
			if (ntohs(hdr_v2->len) < PP2_ADDR_LEN_INET6)
				goto bad_header;

			((struct sockaddr_in6 *)conn->src)->sin6_family = AF_INET6;
			memcpy(&((struct sockaddr_in6 *)conn->src)->sin6_addr, hdr_v2->addr.ip6.src_addr, 16);
			((struct sockaddr_in6 *)conn->src)->sin6_port = hdr_v2->addr.ip6.src_port;
			((struct sockaddr_in6 *)conn->dst)->sin6_family = AF_INET6;
			memcpy(&((struct sockaddr_in6 *)conn->dst)->sin6_addr, hdr_v2->addr.ip6.dst_addr, 16);
			((struct sockaddr_in6 *)conn->dst)->sin6_port = hdr_v2->addr.ip6.dst_port;
			conn->flags |= CO_FL_ADDR_FROM_SET | CO_FL_ADDR_TO_SET;
			tlv_offset = PP2_HEADER_LEN + PP2_ADDR_LEN_INET6;
			tlv_length = ntohs(hdr_v2->len) - PP2_ADDR_LEN_INET6;
			break;
		}

		/* TLV parsing */
		if (tlv_length > 0) {
			while (tlv_offset + TLV_HEADER_SIZE <= trash.data) {
				const struct tlv *tlv_packet = (struct tlv *) &trash.area[tlv_offset];
				const int tlv_len = get_tlv_length(tlv_packet);
				tlv_offset += tlv_len + TLV_HEADER_SIZE;

				switch (tlv_packet->type) {
				case PP2_TYPE_CRC32C: {
					void *tlv_crc32c_p = (void *)tlv_packet->value;
					uint32_t n_crc32c = ntohl(read_u32(tlv_crc32c_p));
					write_u32(tlv_crc32c_p, 0);
					if (hash_crc32c(trash.area, PP2_HEADER_LEN + ntohs(hdr_v2->len)) != n_crc32c)
						goto bad_header;
					break;
				}
#ifdef USE_NS
				case PP2_TYPE_NETNS: {
					const struct netns_entry *ns;
					ns = netns_store_lookup((char*)tlv_packet->value, tlv_len);
					if (ns)
						conn->proxy_netns = ns;
					break;
				}
#endif
				case PP2_TYPE_AUTHORITY: {
					if (tlv_len > PP2_AUTHORITY_MAX)
						goto bad_header;
					conn->proxy_authority = pool_alloc(pool_head_authority);
					if (conn->proxy_authority == NULL)
						goto fail;
					memcpy(conn->proxy_authority, (const char *)tlv_packet->value, tlv_len);
					conn->proxy_authority_len = tlv_len;
					break;
				}
				default:
					break;
				}
			}
		}

		/* unsupported protocol, keep local connection address */
		break;
	case 0x00: /* LOCAL command */
		/* keep local connection address for LOCAL */
		break;
	default:
		goto bad_header; /* not a supported command */
	}

	trash.data = PP2_HEADER_LEN + ntohs(hdr_v2->len);
	goto eat_header;

 eat_header:
	/* remove the PROXY line from the request. For this we re-read the
	 * exact line at once. If we don't get the exact same result, we
	 * fail.
	 */
	while (1) {
		int len2 = recv(conn->handle.fd, trash.area, trash.data, 0);
		if (len2 < 0 && errno == EINTR)
			continue;
		if (len2 != trash.data)
			goto recv_abort;
		break;
	}

	conn->flags &= ~flag;
	conn->flags |= CO_FL_RCVD_PROXY;
	return 1;

 not_ready:
	return 0;

 missing:
	/* Missing data. Since we're using MSG_PEEK, we can only poll again if
	 * we have not read anything. Otherwise we need to fail because we won't
	 * be able to poll anymore.
	 */
	conn->err_code = CO_ER_PRX_TRUNCATED;
	goto fail;

 bad_header:
	/* This is not a valid proxy protocol header */
	conn->err_code = CO_ER_PRX_BAD_HDR;
	goto fail;

 recv_abort:
	conn->err_code = CO_ER_PRX_ABORT;
	conn->flags |= CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
	goto fail;

 fail:
	conn->flags |= CO_FL_ERROR;
	return 0;
}

/* This handshake handler waits a NetScaler Client IP insertion header
 * at the beginning of the raw data stream. The header format is
 * described in doc/netscaler-client-ip-insertion-protocol.txt
 *
 * This line MUST be at the beginning of the buffer and MUST NOT be
 * fragmented.
 *
 * The header line is small and in all cases smaller than the smallest normal
 * TCP MSS. So it MUST always be delivered as one segment, which ensures we
 * can safely use MSG_PEEK and avoid buffering.
 *
 * Once the data is fetched, the values are set in the connection's address
 * fields, and data are removed from the socket's buffer. The function returns
 * zero if it needs to wait for more data or if it fails, or 1 if it completed
 * and removed itself.
 */
int conn_recv_netscaler_cip(struct connection *conn, int flag)
{
	char *line;
	uint32_t hdr_len;
	uint8_t ip_ver;
	int ret;

	if (!conn_ctrl_ready(conn))
		goto fail;

	if (!sockaddr_alloc(&conn->src) || !sockaddr_alloc(&conn->dst))
		goto fail;

	if (!fd_recv_ready(conn->handle.fd))
		goto not_ready;

	while (1) {
		ret = recv(conn->handle.fd, trash.area, trash.size, MSG_PEEK);
		if (ret < 0) {
			if (errno == EINTR)
				continue;
			if (errno == EAGAIN) {
				fd_cant_recv(conn->handle.fd);
				goto not_ready;
			}
			goto recv_abort;
		}
		trash.data = ret;
		break;
	}

	conn->flags &= ~CO_FL_WAIT_L4_CONN;

	if (!trash.data) {
		/* client shutdown */
		conn->err_code = CO_ER_CIP_EMPTY;
		goto fail;
	}

	/* Fail if buffer length is not large enough to contain
	 * CIP magic, header length or
	 * CIP magic, CIP length, CIP type, header length */
	if (trash.data < 12)
		goto missing;

	line = trash.area;

	/* Decode a possible NetScaler Client IP request, fail early if
	 * it does not match */
	if (ntohl(*(uint32_t *)line) != __objt_listener(conn->target)->bind_conf->ns_cip_magic)
		goto bad_magic;

	/* Legacy CIP protocol */
	if ((trash.area[8] & 0xD0) == 0x40) {
		hdr_len = ntohl(*(uint32_t *)(line+4));
		line += 8;
	}
	/* Standard CIP protocol */
	else if (trash.area[8] == 0x00) {
		hdr_len = ntohs(*(uint32_t *)(line+10));
		line += 12;
	}
	/* Unknown CIP protocol */
	else {
		conn->err_code = CO_ER_CIP_BAD_PROTO;
		goto fail;
	}

	/* Fail if buffer length is not large enough to contain
	 * a minimal IP header */
	if (trash.data < 20)
		goto missing;

	/* Get IP version from the first four bits */
	ip_ver = (*line & 0xf0) >> 4;

	if (ip_ver == 4) {
		struct ip *hdr_ip4;
		struct my_tcphdr *hdr_tcp;

		hdr_ip4 = (struct ip *)line;

		if (trash.data < 40 || trash.data < hdr_len) {
			/* Fail if buffer length is not large enough to contain
			 * IPv4 header, TCP header */
			goto missing;
		}
		else if (hdr_ip4->ip_p != IPPROTO_TCP) {
			/* The protocol does not include a TCP header */
			conn->err_code = CO_ER_CIP_BAD_PROTO;
			goto fail;
		}

		hdr_tcp = (struct my_tcphdr *)(line + (hdr_ip4->ip_hl * 4));

		/* update the session's addresses and mark them set */
		((struct sockaddr_in *)conn->src)->sin_family = AF_INET;
		((struct sockaddr_in *)conn->src)->sin_addr.s_addr = hdr_ip4->ip_src.s_addr;
		((struct sockaddr_in *)conn->src)->sin_port = hdr_tcp->source;

		((struct sockaddr_in *)conn->dst)->sin_family = AF_INET;
		((struct sockaddr_in *)conn->dst)->sin_addr.s_addr = hdr_ip4->ip_dst.s_addr;
		((struct sockaddr_in *)conn->dst)->sin_port = hdr_tcp->dest;

		conn->flags |= CO_FL_ADDR_FROM_SET | CO_FL_ADDR_TO_SET;
	}
	else if (ip_ver == 6) {
		struct ip6_hdr *hdr_ip6;
		struct my_tcphdr *hdr_tcp;

		hdr_ip6 = (struct ip6_hdr *)line;

		if (trash.data < 60 || trash.data < hdr_len) {
			/* Fail if buffer length is not large enough to contain
			 * IPv6 header, TCP header */
			goto missing;
		}
		else if (hdr_ip6->ip6_nxt != IPPROTO_TCP) {
			/* The protocol does not include a TCP header */
			conn->err_code = CO_ER_CIP_BAD_PROTO;
			goto fail;
		}

		hdr_tcp = (struct my_tcphdr *)(line + sizeof(struct ip6_hdr));

		/* update the session's addresses and mark them set */
		((struct sockaddr_in6 *)conn->src)->sin6_family = AF_INET6;
		((struct sockaddr_in6 *)conn->src)->sin6_addr = hdr_ip6->ip6_src;
		((struct sockaddr_in6 *)conn->src)->sin6_port = hdr_tcp->source;

		((struct sockaddr_in6 *)conn->dst)->sin6_family = AF_INET6;
		((struct sockaddr_in6 *)conn->dst)->sin6_addr = hdr_ip6->ip6_dst;
		((struct sockaddr_in6 *)conn->dst)->sin6_port = hdr_tcp->dest;

		conn->flags |= CO_FL_ADDR_FROM_SET | CO_FL_ADDR_TO_SET;
	}
	else {
		/* The protocol does not match something known (IPv4/IPv6) */
		conn->err_code = CO_ER_CIP_BAD_PROTO;
		goto fail;
	}

	line += hdr_len;
	trash.data = line - trash.area;

	/* remove the NetScaler Client IP header from the request. For this
	 * we re-read the exact line at once. If we don't get the exact same
	 * result, we fail.
	 */
	while (1) {
		int len2 = recv(conn->handle.fd, trash.area, trash.data, 0);
		if (len2 < 0 && errno == EINTR)
			continue;
		if (len2 != trash.data)
			goto recv_abort;
		break;
	}

	conn->flags &= ~flag;
	return 1;

 not_ready:
	return 0;

 missing:
	/* Missing data. Since we're using MSG_PEEK, we can only poll again if
	 * we have not read anything. Otherwise we need to fail because we won't
	 * be able to poll anymore.
	 */
	conn->err_code = CO_ER_CIP_TRUNCATED;
	goto fail;

 bad_magic:
	conn->err_code = CO_ER_CIP_BAD_MAGIC;
	goto fail;

 recv_abort:
	conn->err_code = CO_ER_CIP_ABORT;
	conn->flags |= CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
	goto fail;

 fail:
	conn->flags |= CO_FL_ERROR;
	return 0;
}


int conn_send_socks4_proxy_request(struct connection *conn)
{
	struct socks4_request req_line;

	if (!conn_ctrl_ready(conn))
		goto out_error;

	if (!conn_get_dst(conn))
		goto out_error;

	req_line.version = 0x04;
	req_line.command = 0x01;
	req_line.port    = get_net_port(conn->dst);
	req_line.ip      = is_inet_addr(conn->dst);
	memcpy(req_line.user_id, "HAProxy\0", 8);

	if (conn->send_proxy_ofs > 0) {
		/*
		 * This is the first call to send the request
		 */
		conn->send_proxy_ofs = -(int)sizeof(req_line);
	}

	if (conn->send_proxy_ofs < 0) {
		int ret = 0;

		/* we are sending the socks4_req_line here. If the data layer
		 * has a pending write, we'll also set MSG_MORE.
		 */
		ret = conn_sock_send(
				conn,
				((char *)(&req_line)) + (sizeof(req_line)+conn->send_proxy_ofs),
				-conn->send_proxy_ofs,
				(conn->subs && conn->subs->events & SUB_RETRY_SEND) ? MSG_MORE : 0);

		DPRINTF(stderr, "SOCKS PROXY HS FD[%04X]: Before send remain is [%d], sent [%d]\n",
				conn->handle.fd, -conn->send_proxy_ofs, ret);

		if (ret < 0) {
			goto out_error;
		}

		conn->send_proxy_ofs += ret; /* becomes zero once complete */
		if (conn->send_proxy_ofs != 0) {
			goto out_wait;
		}
	}

	/* OK we've the whole request sent */
	conn->flags &= ~CO_FL_SOCKS4_SEND;

	/* The connection is ready now, simply return and let the connection
	 * handler notify upper layers if needed.
	 */
	conn->flags &= ~CO_FL_WAIT_L4_CONN;

	if (conn->flags & CO_FL_SEND_PROXY) {
		/*
		 * Get the send_proxy_ofs ready for the send_proxy due to we are
		 * reusing the "send_proxy_ofs", and SOCKS4 handshake should be done
		 * before sending PROXY Protocol.
		 */
		conn->send_proxy_ofs = 1;
	}
	return 1;

 out_error:
	/* Write error on the file descriptor */
	conn->flags |= CO_FL_ERROR;
	if (conn->err_code == CO_ER_NONE) {
		conn->err_code = CO_ER_SOCKS4_SEND;
	}
	return 0;

 out_wait:
	return 0;
}

int conn_recv_socks4_proxy_response(struct connection *conn)
{
	char line[SOCKS4_HS_RSP_LEN];
	int ret;

	if (!conn_ctrl_ready(conn))
		goto fail;

	if (!fd_recv_ready(conn->handle.fd))
		goto not_ready;

	while (1) {
		/* SOCKS4 Proxy will response with 8 bytes, 0x00 | 0x5A | 0x00 0x00 | 0x00 0x00 0x00 0x00
		 * Try to peek into it, before all 8 bytes ready.
		 */
		ret = recv(conn->handle.fd, line, SOCKS4_HS_RSP_LEN, MSG_PEEK);

		if (ret == 0) {
			/* the socket has been closed or shutdown for send */
			DPRINTF(stderr, "SOCKS PROXY HS FD[%04X]: Received ret[%d], errno[%d], looks like the socket has been closed or shutdown for send\n",
					conn->handle.fd, ret, errno);
			if (conn->err_code == CO_ER_NONE) {
				conn->err_code = CO_ER_SOCKS4_RECV;
			}
			goto fail;
		}

		if (ret > 0) {
			if (ret == SOCKS4_HS_RSP_LEN) {
				DPRINTF(stderr, "SOCKS PROXY HS FD[%04X]: Received 8 bytes, the response is [%02X|%02X|%02X %02X|%02X %02X %02X %02X]\n",
						conn->handle.fd, line[0], line[1], line[2], line[3], line[4], line[5], line[6], line[7]);
			}else{
				DPRINTF(stderr, "SOCKS PROXY HS FD[%04X]: Received ret[%d], first byte is [%02X], last bye is [%02X]\n", conn->handle.fd, ret, line[0], line[ret-1]);
			}
		} else {
			DPRINTF(stderr, "SOCKS PROXY HS FD[%04X]: Received ret[%d], errno[%d]\n", conn->handle.fd, ret, errno);
		}

		if (ret < 0) {
			if (errno == EINTR) {
				continue;
			}
			if (errno == EAGAIN) {
				fd_cant_recv(conn->handle.fd);
				goto not_ready;
			}
			goto recv_abort;
		}
		break;
	}

	conn->flags &= ~CO_FL_WAIT_L4_CONN;

	if (ret < SOCKS4_HS_RSP_LEN) {
		/* Missing data. Since we're using MSG_PEEK, we can only poll again if
		 * we are not able to read enough data.
		 */
		goto not_ready;
	}

	/*
	 * Base on the SOCSK4 protocol:
	 *
	 *			+----+----+----+----+----+----+----+----+
	 *			| VN | CD | DSTPORT |      DSTIP        |
	 *			+----+----+----+----+----+----+----+----+
	 *	# of bytes:	   1    1      2              4
	 *	VN is the version of the reply code and should be 0. CD is the result
	 *	code with one of the following values:
	 *	90: request granted
	 *	91: request rejected or failed
	 *	92: request rejected becasue SOCKS server cannot connect to identd on the client
	 *	93: request rejected because the client program and identd report different user-ids
	 *	The remaining fields are ignored.
	 */
	if (line[1] != 90) {
		conn->flags &= ~CO_FL_SOCKS4_RECV;

		DPRINTF(stderr, "SOCKS PROXY HS FD[%04X]: FAIL, the response is [%02X|%02X|%02X %02X|%02X %02X %02X %02X]\n",
				conn->handle.fd, line[0], line[1], line[2], line[3], line[4], line[5], line[6], line[7]);
		if (conn->err_code == CO_ER_NONE) {
			conn->err_code = CO_ER_SOCKS4_DENY;
		}
		goto fail;
	}

	/* remove the 8 bytes response from the stream */
	while (1) {
		ret = recv(conn->handle.fd, line, SOCKS4_HS_RSP_LEN, 0);
		if (ret < 0 && errno == EINTR) {
			continue;
		}
		if (ret != SOCKS4_HS_RSP_LEN) {
			if (conn->err_code == CO_ER_NONE) {
				conn->err_code = CO_ER_SOCKS4_RECV;
			}
			goto fail;
		}
		break;
	}

	conn->flags &= ~CO_FL_SOCKS4_RECV;
	return 1;

 not_ready:
	return 0;

 recv_abort:
	if (conn->err_code == CO_ER_NONE) {
		conn->err_code = CO_ER_SOCKS4_ABORT;
	}
	conn->flags |= (CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH);
	goto fail;

 fail:
	conn->flags |= CO_FL_ERROR;
	return 0;
}

/* Note: <remote> is explicitly allowed to be NULL */
int make_proxy_line(char *buf, int buf_len, struct server *srv, struct connection *remote)
{
	int ret = 0;

	if (srv && (srv->pp_opts & SRV_PP_V2)) {
		ret = make_proxy_line_v2(buf, buf_len, srv, remote);
	}
	else {
		if (remote && conn_get_src(remote) && conn_get_dst(remote))
			ret = make_proxy_line_v1(buf, buf_len, remote->src, remote->dst);
		else
			ret = make_proxy_line_v1(buf, buf_len, NULL, NULL);
	}

	return ret;
}

/* Makes a PROXY protocol line from the two addresses. The output is sent to
 * buffer <buf> for a maximum size of <buf_len> (including the trailing zero).
 * It returns the number of bytes composing this line (including the trailing
 * LF), or zero in case of failure (eg: not enough space). It supports TCP4,
 * TCP6 and "UNKNOWN" formats. If any of <src> or <dst> is null, UNKNOWN is
 * emitted as well.
 */
int make_proxy_line_v1(char *buf, int buf_len, struct sockaddr_storage *src, struct sockaddr_storage *dst)
{
	int ret = 0;
	char * protocol;
	char src_str[MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN)];
	char dst_str[MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN)];
	in_port_t src_port;
	in_port_t dst_port;

	if (   !src
	    || !dst
	    || (src->ss_family != AF_INET && src->ss_family != AF_INET6)
	    || (dst->ss_family != AF_INET && dst->ss_family != AF_INET6)) {
		/* unknown family combination */
		ret = snprintf(buf, buf_len, "PROXY UNKNOWN\r\n");
		if (ret >= buf_len)
			return 0;

		return ret;
	}

	/* IPv4 for both src and dst */
	if (src->ss_family == AF_INET && dst->ss_family == AF_INET) {
		protocol = "TCP4";
		if (!inet_ntop(AF_INET, &((struct sockaddr_in *)src)->sin_addr, src_str, sizeof(src_str)))
			return 0;
		src_port = ((struct sockaddr_in *)src)->sin_port;
		if (!inet_ntop(AF_INET, &((struct sockaddr_in *)dst)->sin_addr, dst_str, sizeof(dst_str)))
			return 0;
		dst_port = ((struct sockaddr_in *)dst)->sin_port;
	}
	/* IPv6 for at least one of src and dst */
	else {
		struct in6_addr tmp;

		protocol = "TCP6";

		if (src->ss_family == AF_INET) {
			/* Convert src to IPv6 */
			v4tov6(&tmp, &((struct sockaddr_in *)src)->sin_addr);
			src_port = ((struct sockaddr_in *)src)->sin_port;
		}
		else {
			tmp = ((struct sockaddr_in6 *)src)->sin6_addr;
			src_port = ((struct sockaddr_in6 *)src)->sin6_port;
		}

		if (!inet_ntop(AF_INET6, &tmp, src_str, sizeof(src_str)))
			return 0;

		if (dst->ss_family == AF_INET) {
			/* Convert dst to IPv6 */
			v4tov6(&tmp, &((struct sockaddr_in *)dst)->sin_addr);
			dst_port = ((struct sockaddr_in *)dst)->sin_port;
		}
		else {
			tmp = ((struct sockaddr_in6 *)dst)->sin6_addr;
			dst_port = ((struct sockaddr_in6 *)dst)->sin6_port;
		}

		if (!inet_ntop(AF_INET6, &tmp, dst_str, sizeof(dst_str)))
			return 0;
	}

	ret = snprintf(buf, buf_len, "PROXY %s %s %s %u %u\r\n", protocol, src_str, dst_str, ntohs(src_port), ntohs(dst_port));
	if (ret >= buf_len)
		return 0;

	return ret;
}

static int make_tlv(char *dest, int dest_len, char type, uint16_t length, const char *value)
{
	struct tlv *tlv;

	if (!dest || (length + sizeof(*tlv) > dest_len))
		return 0;

	tlv = (struct tlv *)dest;

	tlv->type = type;
	tlv->length_hi = length >> 8;
	tlv->length_lo = length & 0x00ff;
	memcpy(tlv->value, value, length);
	return length + sizeof(*tlv);
}

/* Note: <remote> is explicitly allowed to be NULL */
int make_proxy_line_v2(char *buf, int buf_len, struct server *srv, struct connection *remote)
{
	const char pp2_signature[] = PP2_SIGNATURE;
	void *tlv_crc32c_p = NULL;
	int ret = 0;
	struct proxy_hdr_v2 *hdr = (struct proxy_hdr_v2 *)buf;
	struct sockaddr_storage null_addr = { .ss_family = 0 };
	struct sockaddr_storage *src = &null_addr;
	struct sockaddr_storage *dst = &null_addr;
	const char *value;
	int value_len;

	if (buf_len < PP2_HEADER_LEN)
		return 0;
	memcpy(hdr->sig, pp2_signature, PP2_SIGNATURE_LEN);

	if (remote && conn_get_src(remote) && conn_get_dst(remote)) {
		src = remote->src;
		dst = remote->dst;
	}

	/* At least one of src or dst is not of AF_INET or AF_INET6 */
	if (  !src
	   || !dst
	   || (src->ss_family != AF_INET && src->ss_family != AF_INET6)
	   || (dst->ss_family != AF_INET && dst->ss_family != AF_INET6)) {
		if (buf_len < PP2_HDR_LEN_UNSPEC)
			return 0;
		hdr->ver_cmd = PP2_VERSION | PP2_CMD_LOCAL;
		hdr->fam = PP2_FAM_UNSPEC | PP2_TRANS_UNSPEC;
		ret = PP2_HDR_LEN_UNSPEC;
	}
	else {
		/* IPv4 for both src and dst */
		if (src->ss_family == AF_INET && dst->ss_family == AF_INET) {
			if (buf_len < PP2_HDR_LEN_INET)
				return 0;
			hdr->ver_cmd = PP2_VERSION | PP2_CMD_PROXY;
			hdr->fam = PP2_FAM_INET | PP2_TRANS_STREAM;
			hdr->addr.ip4.src_addr = ((struct sockaddr_in *)src)->sin_addr.s_addr;
			hdr->addr.ip4.src_port = ((struct sockaddr_in *)src)->sin_port;
			hdr->addr.ip4.dst_addr = ((struct sockaddr_in *)dst)->sin_addr.s_addr;
			hdr->addr.ip4.dst_port = ((struct sockaddr_in *)dst)->sin_port;
			ret = PP2_HDR_LEN_INET;
		}
		/* IPv6 for at least one of src and dst */
		else {
			struct in6_addr tmp;

			if (buf_len < PP2_HDR_LEN_INET6)
				return 0;
			hdr->ver_cmd = PP2_VERSION | PP2_CMD_PROXY;
			hdr->fam = PP2_FAM_INET6 | PP2_TRANS_STREAM;
			if (src->ss_family == AF_INET) {
				v4tov6(&tmp, &((struct sockaddr_in *)src)->sin_addr);
				memcpy(hdr->addr.ip6.src_addr, &tmp, 16);
				hdr->addr.ip6.src_port = ((struct sockaddr_in *)src)->sin_port;
			}
			else {
				memcpy(hdr->addr.ip6.src_addr, &((struct sockaddr_in6 *)src)->sin6_addr, 16);
				hdr->addr.ip6.src_port = ((struct sockaddr_in6 *)src)->sin6_port;
			}
			if (dst->ss_family == AF_INET) {
				v4tov6(&tmp, &((struct sockaddr_in *)dst)->sin_addr);
				memcpy(hdr->addr.ip6.dst_addr, &tmp, 16);
				hdr->addr.ip6.dst_port = ((struct sockaddr_in *)dst)->sin_port;
			}
			else {
				memcpy(hdr->addr.ip6.dst_addr, &((struct sockaddr_in6 *)dst)->sin6_addr, 16);
				hdr->addr.ip6.dst_port = ((struct sockaddr_in6 *)dst)->sin6_port;
			}

			ret = PP2_HDR_LEN_INET6;
		}
	}

	if (srv->pp_opts & SRV_PP_V2_CRC32C) {
		uint32_t zero_crc32c = 0;
		if ((buf_len - ret) < sizeof(struct tlv))
			return 0;
		tlv_crc32c_p = (void *)((struct tlv *)&buf[ret])->value;
		ret += make_tlv(&buf[ret], (buf_len - ret), PP2_TYPE_CRC32C, sizeof(zero_crc32c), (const char *)&zero_crc32c);
	}

	if (remote && conn_get_alpn(remote, &value, &value_len)) {
		if ((buf_len - ret) < sizeof(struct tlv))
			return 0;
		ret += make_tlv(&buf[ret], (buf_len - ret), PP2_TYPE_ALPN, value_len, value);
	}

	if (srv->pp_opts & SRV_PP_V2_AUTHORITY) {
		value = NULL;
		if (remote && remote->proxy_authority) {
			value = remote->proxy_authority;
			value_len = remote->proxy_authority_len;
		}
#ifdef USE_OPENSSL
		else {
			if ((value = ssl_sock_get_sni(remote)))
				value_len = strlen(value);
		}
#endif
		if (value) {
			if ((buf_len - ret) < sizeof(struct tlv))
				return 0;
			ret += make_tlv(&buf[ret], (buf_len - ret), PP2_TYPE_AUTHORITY, value_len, value);
		}
	}

#ifdef USE_OPENSSL
	if (srv->pp_opts & SRV_PP_V2_SSL) {
		struct tlv_ssl *tlv;
		int ssl_tlv_len = 0;
		if ((buf_len - ret) < sizeof(struct tlv_ssl))
			return 0;
		tlv = (struct tlv_ssl *)&buf[ret];
		memset(tlv, 0, sizeof(struct tlv_ssl));
		ssl_tlv_len += sizeof(struct tlv_ssl);
		tlv->tlv.type = PP2_TYPE_SSL;
		if (ssl_sock_is_ssl(remote)) {
			tlv->client |= PP2_CLIENT_SSL;
			value = ssl_sock_get_proto_version(remote);
			if (value) {
				ssl_tlv_len += make_tlv(&buf[ret+ssl_tlv_len], (buf_len-ret-ssl_tlv_len), PP2_SUBTYPE_SSL_VERSION, strlen(value), value);
			}
			if (ssl_sock_get_cert_used_sess(remote)) {
				tlv->client |= PP2_CLIENT_CERT_SESS;
				tlv->verify = htonl(ssl_sock_get_verify_result(remote));
				if (ssl_sock_get_cert_used_conn(remote))
					tlv->client |= PP2_CLIENT_CERT_CONN;
			}
			if (srv->pp_opts & SRV_PP_V2_SSL_CN) {
				struct buffer *cn_trash = get_trash_chunk();
				if (ssl_sock_get_remote_common_name(remote, cn_trash) > 0) {
					ssl_tlv_len += make_tlv(&buf[ret+ssl_tlv_len], (buf_len - ret - ssl_tlv_len), PP2_SUBTYPE_SSL_CN,
								cn_trash->data,
								cn_trash->area);
				}
			}
			if (srv->pp_opts & SRV_PP_V2_SSL_KEY_ALG) {
				struct buffer *pkey_trash = get_trash_chunk();
				if (ssl_sock_get_pkey_algo(remote, pkey_trash) > 0) {
					ssl_tlv_len += make_tlv(&buf[ret+ssl_tlv_len], (buf_len - ret - ssl_tlv_len), PP2_SUBTYPE_SSL_KEY_ALG,
								pkey_trash->data,
								pkey_trash->area);
				}
			}
			if (srv->pp_opts & SRV_PP_V2_SSL_SIG_ALG) {
				value = ssl_sock_get_cert_sig(remote);
				if (value) {
					ssl_tlv_len += make_tlv(&buf[ret+ssl_tlv_len], (buf_len - ret - ssl_tlv_len), PP2_SUBTYPE_SSL_SIG_ALG, strlen(value), value);
				}
			}
			if (srv->pp_opts & SRV_PP_V2_SSL_CIPHER) {
				value = ssl_sock_get_cipher_name(remote);
				if (value) {
					ssl_tlv_len += make_tlv(&buf[ret+ssl_tlv_len], (buf_len - ret - ssl_tlv_len), PP2_SUBTYPE_SSL_CIPHER, strlen(value), value);
				}
			}
		}
		tlv->tlv.length_hi = (uint16_t)(ssl_tlv_len - sizeof(struct tlv)) >> 8;
		tlv->tlv.length_lo = (uint16_t)(ssl_tlv_len - sizeof(struct tlv)) & 0x00ff;
		ret += ssl_tlv_len;
	}
#endif

#ifdef USE_NS
	if (remote && (remote->proxy_netns)) {
		if ((buf_len - ret) < sizeof(struct tlv))
			return 0;
		ret += make_tlv(&buf[ret], (buf_len - ret), PP2_TYPE_NETNS, remote->proxy_netns->name_len, remote->proxy_netns->node.key);
	}
#endif

	hdr->len = htons((uint16_t)(ret - PP2_HEADER_LEN));

	if (tlv_crc32c_p) {
		write_u32(tlv_crc32c_p, htonl(hash_crc32c(buf, ret)));
	}

	return ret;
}

/* return the major HTTP version as 1 or 2 depending on how the request arrived
 * before being processed.
 */
static int
smp_fetch_fc_http_major(const struct arg *args, struct sample *smp, const char *kw, void *private)
{
	struct connection *conn = (kw[0] != 'b') ? objt_conn(smp->sess->origin) :
										smp->strm ? cs_conn(objt_cs(smp->strm->si[1].end)) : NULL;

	smp->data.type = SMP_T_SINT;
	smp->data.u.sint = (conn && strcmp(conn_get_mux_name(conn), "H2") == 0) ? 2 : 1;
	return 1;
}

/* fetch if the received connection used a PROXY protocol header */
int smp_fetch_fc_rcvd_proxy(const struct arg *args, struct sample *smp, const char *kw, void *private)
{
	struct connection *conn;

	conn = objt_conn(smp->sess->origin);
	if (!conn)
		return 0;

	if (conn->flags & CO_FL_WAIT_XPRT) {
		smp->flags |= SMP_F_MAY_CHANGE;
		return 0;
	}

	smp->flags = 0;
	smp->data.type = SMP_T_BOOL;
	smp->data.u.sint = (conn->flags & CO_FL_RCVD_PROXY) ? 1 : 0;

	return 1;
}

/* fetch the authority TLV from a PROXY protocol header */
int smp_fetch_fc_pp_authority(const struct arg *args, struct sample *smp, const char *kw, void *private)
{
	struct connection *conn;

	conn = objt_conn(smp->sess->origin);
	if (!conn)
		return 0;

	if (conn->flags & CO_FL_WAIT_XPRT) {
		smp->flags |= SMP_F_MAY_CHANGE;
		return 0;
	}

	if (conn->proxy_authority == NULL)
		return 0;

	smp->flags = 0;
	smp->data.type = SMP_T_STR;
	smp->data.u.str.area = conn->proxy_authority;
	smp->data.u.str.data = conn->proxy_authority_len;

	return 1;
}

/* Note: must not be declared <const> as its list will be overwritten.
 * Note: fetches that may return multiple types must be declared as the lowest
 * common denominator, the type that can be casted into all other ones. For
 * instance v4/v6 must be declared v4.
 */
static struct sample_fetch_kw_list sample_fetch_keywords = {ILH, {
	{ "fc_http_major", smp_fetch_fc_http_major, 0, NULL, SMP_T_SINT, SMP_USE_L4CLI },
	{ "bc_http_major", smp_fetch_fc_http_major, 0, NULL, SMP_T_SINT, SMP_USE_L4SRV },
	{ "fc_rcvd_proxy", smp_fetch_fc_rcvd_proxy, 0, NULL, SMP_T_BOOL, SMP_USE_L4CLI },
	{ "fc_pp_authority", smp_fetch_fc_pp_authority, 0, NULL, SMP_T_STR, SMP_USE_L4CLI },
	{ /* END */ },
}};

INITCALL1(STG_REGISTER, sample_register_fetches, &sample_fetch_keywords);