diff options
Diffstat (limited to 'src/receive.c')
| -rw-r--r-- | src/receive.c | 185 |
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); +} |