Move more code out of fastd.c

1 files changed, 185 insertions, 0 deletions

diff --git a/src/receive.c b/src/receive.c
new file mode 100644
index 0000000..fc835eb
--- /dev/null
+++ b/src/receive.c
@@ -0,0 +1,185 @@
+/*
+  Copyright (c) 2012-2013, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#include "fastd.h"
+#include "handshake.h"
+#include "packet.h"
+#include "peer.h"
+
+
+static inline void handle_socket_control(fastd_context_t *ctx, struct msghdr *message, const fastd_socket_t *sock, fastd_peer_address_t *local_addr) {
+	memset(local_addr, 0, sizeof(fastd_peer_address_t));
+
+	const char *end = (char*)message->msg_control + message->msg_controllen;
+
+	struct cmsghdr *cmsg;
+	for (cmsg = CMSG_FIRSTHDR(message); cmsg; cmsg = CMSG_NXTHDR(message, cmsg)) {
+		if ((char*)cmsg + sizeof(*cmsg) > end)
+			return;
+
+		if (cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_PKTINFO) {
+			struct in_pktinfo *pktinfo = (struct in_pktinfo*)CMSG_DATA(cmsg);
+			if ((char*)pktinfo + sizeof(*pktinfo) > end)
+				return;
+
+			local_addr->in.sin_family = AF_INET;
+			local_addr->in.sin_addr = pktinfo->ipi_addr;
+			local_addr->in.sin_port = fastd_peer_address_get_port(sock->bound_addr);
+
+			return;
+		}
+
+		if (cmsg->cmsg_level == IPPROTO_IPV6 && cmsg->cmsg_type == IPV6_PKTINFO) {
+			struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(cmsg);
+			if ((char*)pktinfo + sizeof(*pktinfo) > end)
+				return;
+
+			local_addr->in6.sin6_family = AF_INET6;
+			local_addr->in6.sin6_addr = pktinfo->ipi6_addr;
+			local_addr->in6.sin6_port = fastd_peer_address_get_port(sock->bound_addr);
+
+			if (IN6_IS_ADDR_LINKLOCAL(&local_addr->in6.sin6_addr))
+				local_addr->in6.sin6_scope_id = pktinfo->ipi6_ifindex;
+
+			return;
+		}
+	}
+}
+
+static inline void handle_socket_receive_known(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, fastd_buffer_t buffer) {
+	if (!fastd_peer_may_connect(ctx, peer)) {
+		fastd_buffer_free(buffer);
+		return;
+	}
+
+	const uint8_t *packet_type = buffer.data;
+	fastd_buffer_push_head(ctx, &buffer, 1);
+
+	switch (*packet_type) {
+	case PACKET_DATA:
+		if (!fastd_peer_is_established(peer) || !fastd_peer_address_equal(&peer->local_address, local_addr)) {
+			fastd_buffer_free(buffer);
+			ctx->conf->protocol->handshake_init(ctx, sock, local_addr, remote_addr, NULL);
+			return;
+		}
+
+		ctx->conf->protocol->handle_recv(ctx, peer, buffer);
+		break;
+
+	case PACKET_HANDSHAKE:
+		fastd_handshake_handle(ctx, sock, local_addr, remote_addr, peer, buffer);
+	}
+}
+
+static inline bool is_unknown_peer_valid(fastd_context_t *ctx, const fastd_peer_address_t *remote_addr) {
+	return ctx->conf->has_floating || ctx->conf->on_verify;
+}
+
+static inline void handle_socket_receive_unknown(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_buffer_t buffer) {
+	const uint8_t *packet_type = buffer.data;
+	fastd_buffer_push_head(ctx, &buffer, 1);
+
+	switch (*packet_type) {
+	case PACKET_DATA:
+		fastd_buffer_free(buffer);
+		ctx->conf->protocol->handshake_init(ctx, sock, local_addr, remote_addr, NULL);
+		break;
+
+	case PACKET_HANDSHAKE:
+		fastd_handshake_handle(ctx, sock, local_addr, remote_addr, NULL, buffer);
+	}
+}
+
+static inline void handle_socket_receive(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_buffer_t buffer) {
+	fastd_peer_t *peer = NULL;
+
+	if (sock->peer) {
+		if (!fastd_peer_address_equal(&sock->peer->address, remote_addr)) {
+			fastd_buffer_free(buffer);
+			return;
+		}
+
+		peer = sock->peer;
+	}
+	else {
+		for (peer = ctx->peers; peer; peer = peer->next) {
+			if (fastd_peer_address_equal(&peer->address, remote_addr))
+				break;
+		}
+	}
+
+	if (peer) {
+		handle_socket_receive_known(ctx, sock, local_addr, remote_addr, peer, buffer);
+	}
+	else if(is_unknown_peer_valid(ctx, remote_addr)) {
+		handle_socket_receive_unknown(ctx, sock, local_addr, remote_addr, buffer);
+	}
+	else  {
+		pr_debug(ctx, "received packet from unknown peer %I", remote_addr);
+		fastd_buffer_free(buffer);
+	}
+}
+
+void fastd_receive(fastd_context_t *ctx, fastd_socket_t *sock) {
+	size_t max_len = PACKET_TYPE_LEN + ctx->conf->max_packet_size;
+	fastd_buffer_t buffer = fastd_buffer_alloc(ctx, max_len, ctx->conf->min_decrypt_head_space, ctx->conf->min_decrypt_tail_space);
+	fastd_peer_address_t local_addr;
+	fastd_peer_address_t recvaddr;
+	struct iovec buffer_vec = { .iov_base = buffer.data, .iov_len = buffer.len };
+	char cbuf[1024];
+
+	struct msghdr message = {
+		.msg_name = &recvaddr,
+		.msg_namelen = sizeof(recvaddr),
+		.msg_iov = &buffer_vec,
+		.msg_iovlen = 1,
+		.msg_control = cbuf,
+		.msg_controllen = sizeof(cbuf),
+	};
+
+	ssize_t len = recvmsg(sock->fd, &message, 0);
+	if (len <= 0) {
+		if (len < 0 && errno != EINTR)
+			pr_warn_errno(ctx, "recvmsg");
+
+		fastd_buffer_free(buffer);
+		return;
+	}
+
+	buffer.len = len;
+
+	handle_socket_control(ctx, &message, sock, &local_addr);
+
+	if (!local_addr.sa.sa_family) {
+		pr_error(ctx, "received packet without packet info");
+		fastd_buffer_free(buffer);
+		return;
+	}
+
+	fastd_peer_address_simplify(&recvaddr);
+
+	handle_socket_receive(ctx, sock, &local_addr, &recvaddr, buffer);
+}