--- /dev/null
+#include <linux/module.h>
+#include <linux/version.h>
+#include <net/sock.h>
+#include <net/protocol.h>
+#include <net/ip.h>
+#include <net/route.h>
+
+#include "mptp.h"
+#include "debug.h"
+
+MODULE_DESCRIPTION("Multi-Party Transport Protocol");
+MODULE_AUTHOR("Adrian Bondrescu/Cornel Mercan");
+MODULE_LICENSE("GPL");
+
+struct mptp_sock {
+ struct inet_sock sock;
+ /* mptp socket speciffic data */
+ uint8_t src;
+ uint8_t dst;
+};
+
+static struct mptp_sock * sock_port_map[MAX_MPTP_PORT];
+
+static inline struct mptp_sock * mptp_sk(struct sock * sock)
+{
+ return (struct mptp_sock *)(sock);
+}
+
+static inline struct mptphdr * mptp_hdr(const struct sk_buff * skb)
+{
+ return (struct mptphdr *) skb_transport_header(skb);
+}
+
+static inline uint8_t get_next_free_port(void)
+{
+ int i;
+ for (i = MIN_MPTP_PORT; i < MAX_MPTP_PORT; i ++)
+ if (sock_port_map[i] == NULL)
+ return i;
+ return 0;
+}
+
+static inline void mptp_unhash(uint8_t port)
+{
+ sock_port_map[port] = NULL;
+}
+
+static inline void mptp_hash(uint8_t port, struct mptp_sock *ssh)
+{
+ sock_port_map[port] = ssh;
+}
+
+static inline struct mptp_sock * mptp_lookup(uint8_t port)
+{
+ return sock_port_map[port];
+}
+
+static int mptp_release(struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+ struct mptp_sock * ssk = mptp_sk(sk);
+
+ if (unlikely(!sk))
+ return 0;
+
+ mptp_unhash(ssk->src);
+
+ sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+
+ synchronize_net();
+
+ sock_orphan(sk);
+ sock->sk = NULL;
+
+ skb_queue_purge(&sk->sk_receive_queue);
+
+ log_debug("mptp_release sock=%p\n", sk);
+ sock_put(sk);
+
+ return 0;
+}
+
+static int mptp_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
+{
+ struct sockaddr_mptp *mptp_addr;
+ struct mptp_sock *ssk;
+ int err;
+ uint8_t port;
+
+ if (unlikely(addr_len < sizeof(struct sockaddr_mptp))) {
+ log_error("Invalid size for sockaddr\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ mptp_addr = (struct sockaddr_mptp *) addr;
+
+ port = mptp_addr->dests[0].port;
+
+ if (unlikely(port == 0 || port >= MAX_MPTP_PORT)) {
+ log_error("Invalid value for sockaddr port (%u)\n", port);
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (unlikely(mptp_lookup(port) != NULL)) {
+ log_error("Port %u already in use\n", port);
+ err = -EADDRINUSE;
+ goto out;
+ }
+
+ ssk = mptp_sk(sock->sk);
+ sock->sk->sk_rcvbuf = 10 * 1024 * 1024;
+ ssk->src = port;
+
+ mptp_hash(port, ssk);
+
+ log_debug("Socket %p bound to port %u\n", ssk, port);
+
+ return 0;
+
+out:
+ return err;
+}
+
+static int mptp_connect(struct socket *sock, struct sockaddr *addr, int addr_len, int flags)
+{
+ int err;
+ struct sock * sk;
+ struct inet_sock * isk;
+ struct mptp_sock * ssk;
+
+ log_debug("mptp_connect\n");
+
+ if (unlikely(sock == NULL)) {
+ log_error("Sock is NULL\n");
+ err = -EINVAL;
+ goto out;
+ }
+ sk = sock->sk;
+
+ if (unlikely(sk == NULL)) {
+ log_error("Sock->sk is NULL\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ isk = inet_sk(sk);
+ ssk = mptp_sk(sk);
+
+ if (unlikely(ssk->src != 0)) {
+ log_error("ssk->src is not NULL\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (likely(addr)) {
+ struct sockaddr_mptp * mptp_addr = (struct sockaddr_mptp *) addr;
+
+ if (unlikely(addr_len < sizeof(*mptp_addr) ||
+ addr_len < mptp_addr->count * sizeof(struct mptp_dest) ||
+ mptp_addr->count <= 0)) {
+ log_error("Invalid size or address family\n");
+ err = -EINVAL;
+ goto out;
+ }
+ ssk->dst = mptp_addr->dests[0].port;
+ if (unlikely(ssk->dst == 0 || ssk->dst >= MAX_MPTP_PORT)) {
+ log_error("Invalid value for destination port(%u)\n", ssk->dst);
+ err = -EINVAL;
+ goto out;
+ }
+
+ isk->inet_daddr = mptp_addr->dests[0].addr;
+ log_debug("Received from user space destination port=%u and address=%u\n", ssk->dst, isk->inet_daddr);
+ } else {
+ log_error("Invalid mptp_addr (NULL)\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ ssk->src = get_next_free_port();
+ if (unlikely(ssk->src == 0)) {
+ log_error("No free ports\n");
+ err = -ENOMEM;
+ goto out;
+ }
+
+ mptp_hash(ssk->src, ssk);
+
+ return 0;
+
+out:
+ return err;
+}
+
+static int mptp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len)
+{
+ int err;
+ uint8_t dport;
+ __be32 daddr;
+ uint8_t sport;
+ struct sk_buff * skb;
+ struct sock * sk;
+ struct inet_sock * isk;
+ struct mptp_sock * ssk;
+ struct mptphdr * shdr;
+ int connected = 0;
+ int totlen;
+ struct rtable * rt = NULL;
+ int dests = 0;
+ int i;
+ struct sockaddr_mptp * mptp_addr = NULL;
+
+ if (unlikely(sock == NULL)) {
+ log_error("Sock is NULL\n");
+ err = -EINVAL;
+ goto out;
+ }
+ sk = sock->sk;
+
+ if (unlikely(sk == NULL)) {
+ log_error("Sock->sk is NULL\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ isk = inet_sk(sk);
+ ssk = mptp_sk(sk);
+
+ sport = ssk->src;
+ if (sport == 0) {
+ sport = get_next_free_port();
+ if (unlikely(sport == 0)) {
+ log_error("No free ports\n");
+ err = -ENOMEM;
+ goto out;
+ }
+ }
+
+ if (msg->msg_name) {
+ mptp_addr = (struct sockaddr_mptp *) msg->msg_name;
+
+ if (unlikely(msg->msg_namelen < sizeof(*mptp_addr) ||
+ msg->msg_namelen < mptp_addr->count * sizeof(struct mptp_dest) ||
+ mptp_addr->count <= 0)) {
+ log_error("Invalid size for msg_name\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ dests = mptp_addr->count;
+ } else {
+ BUG();
+ if (unlikely(!ssk->dst || !isk->inet_daddr)) {
+ log_error("No destination port/address\n");
+ err = -EDESTADDRREQ;
+ goto out;
+ }
+ dport = ssk->dst;
+ daddr = isk->inet_daddr;
+
+ log_debug("Got from socket destination port=%u and address=%u\n", dport, daddr);
+ connected = 1;
+ }
+
+ if (msg->msg_iovlen < dests)
+ dests = msg->msg_iovlen;
+
+ for (i = 0; i < dests; i++) {
+ struct mptp_dest *dest = &mptp_addr->dests[i];
+ struct iovec *iov = &msg->msg_iov[i];
+ char *payload;
+
+ dport = dest->port;
+ if (unlikely(dport == 0 || dport >= MAX_MPTP_PORT)) {
+ log_error("Invalid value for destination port(%u)\n", dport);
+ err = -EINVAL;
+ goto out;
+ }
+
+ daddr = dest->addr;
+ log_debug("Received from user space destination port=%u and address=%u\n", dport, daddr);
+
+ len = iov->iov_len;
+ totlen = len + sizeof(struct mptphdr) + sizeof(struct iphdr);
+ skb = sock_alloc_send_skb(sk, totlen, msg->msg_flags & MSG_DONTWAIT, &err);
+ if (unlikely(!skb)) {
+ log_error("sock_alloc_send_skb failed\n");
+ goto out;
+ }
+ log_debug("Allocated %u bytes for skb (payload size=%u)\n", totlen, len);
+
+ skb_reset_network_header(skb);
+ skb_reserve(skb, sizeof(struct iphdr));
+ log_debug("Reseted network header\n");
+ skb_reset_transport_header(skb);
+ skb_put(skb, sizeof(struct mptphdr));
+ log_debug("Reseted transport header\n");
+
+ shdr = (struct mptphdr *) skb_transport_header(skb);
+ shdr->dst = dport;
+ shdr->src = sport;
+ shdr->len = ntohs(len + sizeof(struct mptphdr));
+
+ payload = skb_put(skb, len);
+ log_debug("payload=%p\n", payload);
+
+ err = skb_copy_datagram_from_iovec(skb, sizeof(struct mptphdr), iov, 0, len);
+ if (unlikely(err)) {
+ log_error("skb_copy_datagram_from_iovec failed\n");
+ goto out_free;
+ }
+ log_debug("Copied %u bytes into the skb\n", len);
+
+ if (connected)
+ rt = (struct rtable *) __sk_dst_check(sk, 0);
+
+ if (rt == NULL) {
+ struct flowi fl = { .fl4_dst = daddr,
+ .proto = sk->sk_protocol,
+ .flags = inet_sk_flowi_flags(sk),
+ };
+ err = ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0);
+ if (unlikely(err)) {
+ log_error("Route lookup failed\n");
+ goto out_free;
+ }
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 36)
+ sk_dst_set(sk, dst_clone(&rt->u.dst));
+#else
+ sk_dst_set(sk, dst_clone(&rt->dst));
+#endif
+ }
+
+ skb->local_df = 1;
+ err = ip_queue_xmit(skb);
+ if (likely(!err))
+ log_debug("Sent %u bytes on wire\n", len);
+ else
+ log_error("ip_queue_xmit failed\n");
+ }
+
+ return err;
+
+out_free:
+ kfree(skb);
+
+out:
+ return err;
+}
+
+static int mptp_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len, int flags)
+{
+ struct sk_buff *skb;
+ struct sockaddr_mptp *mptp_addr;
+ struct sock * sk = sock->sk;
+ int err, copied;
+ int i;
+ struct sockaddr_mptp *ret_addr = (struct sockaddr_mptp *) msg->msg_name;
+
+ log_debug("Trying to receive sock=%p sk=%p flags=%d\n", sock, sk, flags);
+
+ skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &err);
+ if (unlikely(!skb)) {
+ log_error("skb_recv_datagram failed with %d\n", err);
+ goto out;
+ }
+
+ for (i = 0; i < msg->msg_iovlen; i++) {
+ log_debug("Received skb %p\n", skb);
+
+ mptp_addr = (struct sockaddr_mptp *) skb->cb;
+
+ copied = skb->len;
+ if (copied > msg->msg_iov[i].iov_len) {
+ copied = msg->msg_iov[i].iov_len;
+ msg->msg_flags |= MSG_TRUNC;
+ }
+
+ err = skb_copy_datagram_iovec(skb, 0, &msg->msg_iov[i], copied);
+ if (unlikely(err)) {
+ log_error("skb_copy_datagram_iovec\n");
+ goto out_free;
+ }
+
+ sock_recv_ts_and_drops(msg, sk, skb);
+
+ if (ret_addr)
+ memcpy(&ret_addr->dests[i], &mptp_addr->dests[0], sizeof(ret_addr->dests[i]));
+
+ err = copied;
+
+out_free:
+ skb_free_datagram(sk, skb);
+
+ skb = skb_recv_datagram(sk, flags, 1, &err);
+ if (likely(err == -EAGAIN)) {
+ log_debug("No more skbs in the queue, returning...\n");
+ err = copied;
+ break;
+ }
+ }
+
+ ret_addr->count = i + 1;
+ msg->msg_namelen = sizeof(struct sockaddr_mptp) + (i + 1) * sizeof(struct mptp_dest);
+
+out:
+ return err;
+}
+
+static int mptp_rcv(struct sk_buff *skb)
+{
+ struct mptphdr *shdr;
+ struct mptp_sock *ssk;
+ __be16 len;
+ uint8_t src, dst;
+ struct sockaddr_mptp * mptp_addr;
+ int err;
+ int addr_size = sizeof(struct sockaddr_mptp) + sizeof(struct mptp_dest);
+
+ if (unlikely(!pskb_may_pull(skb, sizeof(struct mptphdr)))) {
+ log_error("Insufficient space for header\n");
+ goto drop;
+ }
+
+ shdr = (struct mptphdr *) skb->data;
+ len = ntohs(shdr->len);
+
+ if (unlikely(skb->len < len)) {
+ log_error("Malformed packet (packet_len=%u, skb_len=%u)\n", len, skb->len);
+ goto drop;
+ }
+
+ if (unlikely(len < sizeof(struct mptphdr))) {
+ log_error("Malformed packet (packet_len=%u sizeof(mptphdr)=%u\n", len, sizeof(struct mptphdr));
+ goto drop;
+ }
+
+ src = shdr->src;
+ dst = shdr->dst;
+ if (unlikely(src == 0 || dst == 0 || src >= MAX_MPTP_PORT || dst >= MAX_MPTP_PORT)) {
+ log_error("Malformed packet (src=%u, dst=%u)\n", shdr->src, shdr->dst);
+ goto drop;
+ }
+
+ skb_pull(skb, sizeof(struct mptphdr));
+ len -= sizeof(struct mptphdr);
+
+ pskb_trim(skb, len);
+
+ log_debug("Received %u bytes from from port=%u to port=%u\n", len - sizeof(struct mptphdr), src, dst);
+
+ ssk = mptp_lookup(dst);
+ if (ssk == NULL) {
+ log_error("MPTP lookup failed for port %u\n", dst);
+ goto drop;
+ }
+
+ BUG_ON(addr_size > sizeof(skb->cb));
+
+ mptp_addr = (struct sockaddr_mptp *) skb->cb;
+ mptp_addr->dests[0].port = shdr->src;
+ mptp_addr->dests[0].addr = ip_hdr(skb)->saddr;
+
+ log_debug("Setting sin_port=%u, sin_addr=%u\n", ntohs(shdr->src), mptp_addr->dests[0].addr);
+
+ err = ip_queue_rcv_skb((struct sock *) &ssk->sock, skb);
+ if (unlikely(err)) {
+ log_error("ip_queue_rcv_skb failed with %d\n", err);
+ consume_skb(skb);
+ }
+ return NET_RX_SUCCESS;
+
+drop:
+ kfree(skb);
+ return NET_RX_DROP;
+}
+
+static struct proto mptp_prot = {
+ .obj_size = sizeof(struct mptp_sock),
+ .owner = THIS_MODULE,
+ .name = "MPTP",
+};
+
+static const struct proto_ops mptp_ops = {
+ .family = PF_INET,
+ .owner = THIS_MODULE,
+ .release = mptp_release,
+ .bind = mptp_bind,
+ .connect = mptp_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = sock_no_accept,
+ .getname = sock_no_getname,
+ .poll = datagram_poll,
+ .ioctl = sock_no_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .setsockopt = sock_no_setsockopt,
+ .getsockopt = sock_no_getsockopt,
+ .sendmsg = mptp_sendmsg,
+ .recvmsg = mptp_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = sock_no_sendpage,
+};
+
+static const struct net_protocol mptp_protocol = {
+ .handler = mptp_rcv,
+ .no_policy = 1,
+ .netns_ok = 1,
+};
+
+static struct inet_protosw mptp_protosw = {
+ .type = SOCK_DGRAM,
+ .protocol = IPPROTO_MPTP,
+ .prot = &mptp_prot,
+ .ops = &mptp_ops,
+ .no_check = 0,
+};
+
+static int __init mptp_init(void)
+{
+ int rc;
+
+ rc = proto_register(&mptp_prot, 1);
+ if (unlikely(rc)) {
+ log_error("Error registering mptp protocol\n");
+ goto out;
+ }
+
+ rc = inet_add_protocol(&mptp_protocol, IPPROTO_MPTP);
+ if (unlikely(rc)) {
+ log_error("Error adding mptp protocol\n");
+ goto out_unregister;
+ }
+
+ inet_register_protosw(&mptp_protosw);
+ log_debug("MPTP entered\n");
+
+ return 0;
+
+out_unregister:
+ proto_unregister(&mptp_prot);
+
+out:
+ return rc;
+}
+
+static void __exit mptp_exit(void)
+{
+ inet_unregister_protosw(&mptp_protosw);
+
+ inet_del_protocol(&mptp_protocol, IPPROTO_MPTP);
+
+ proto_unregister(&mptp_prot);
+
+ log_debug("MPTP exited\n");
+}
+
+module_init(mptp_init);
+module_exit(mptp_exit);
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