From 833ef3b91de692ef33b800bca6b1569c39dece74 Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Thu, 29 Jul 2021 10:20:49 +0800 Subject: [PATCH] mctp: Populate socket implementation Start filling-out the socket syscalls: bind, sendmsg & recvmsg. This requires an input route implementation, so we add to mctp_route_input, allowing lookups on binds & message tags. This just handles single-packet messages at present, we will add fragmentation in a future change. Signed-off-by: Jeremy Kerr Signed-off-by: David S. Miller --- include/net/mctp.h | 59 ++++++++++ include/net/netns/mctp.h | 13 +++ net/mctp/af_mctp.c | 203 +++++++++++++++++++++++++++++++++-- net/mctp/route.c | 226 ++++++++++++++++++++++++++++++++++++++- 4 files changed, 491 insertions(+), 10 deletions(-) diff --git a/include/net/mctp.h b/include/net/mctp.h index 53f035c8b59c..f2d98f6993c0 100644 --- a/include/net/mctp.h +++ b/include/net/mctp.h @@ -12,6 +12,7 @@ #include #include #include +#include /* MCTP packet definitions */ struct mctp_hdr { @@ -46,6 +47,64 @@ static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb) return (struct mctp_hdr *)skb_network_header(skb); } +/* socket implementation */ +struct mctp_sock { + struct sock sk; + + /* bind() params */ + int bind_net; + mctp_eid_t bind_addr; + __u8 bind_type; + + /* list of mctp_sk_key, for incoming tag lookup. updates protected + * by sk->net->keys_lock + */ + struct hlist_head keys; +}; + +/* Key for matching incoming packets to sockets or reassembly contexts. + * Packets are matched on (src,dest,tag). + * + * Lifetime requirements: + * + * - keys are free()ed via RCU + * + * - a mctp_sk_key contains a reference to a struct sock; this is valid + * for the life of the key. On sock destruction (through unhash), the key is + * removed from lists (see below), and will not be observable after a RCU + * grace period. + * + * any RX occurring within that grace period may still queue to the socket, + * but will hit the SOCK_DEAD case before the socket is freed. + * + * - these mctp_sk_keys appear on two lists: + * 1) the struct mctp_sock->keys list + * 2) the struct netns_mctp->keys list + * + * updates to either list are performed under the netns_mctp->keys + * lock. + * + * - there is a single destruction path for a mctp_sk_key - through socket + * unhash (see mctp_sk_unhash). This performs the list removal under + * keys_lock. + */ +struct mctp_sk_key { + mctp_eid_t peer_addr; + mctp_eid_t local_addr; + __u8 tag; /* incoming tag match; invert TO for local */ + + /* we hold a ref to sk when set */ + struct sock *sk; + + /* routing lookup list */ + struct hlist_node hlist; + + /* per-socket list */ + struct hlist_node sklist; + + struct rcu_head rcu; +}; + struct mctp_skb_cb { unsigned int magic; unsigned int net; diff --git a/include/net/netns/mctp.h b/include/net/netns/mctp.h index 2f5ebeeb320e..14ae6d37e52a 100644 --- a/include/net/netns/mctp.h +++ b/include/net/netns/mctp.h @@ -12,6 +12,19 @@ struct netns_mctp { /* Only updated under RTNL, entries freed via RCU */ struct list_head routes; + /* Bound sockets: list of sockets bound by type. + * This list is updated from non-atomic contexts (under bind_lock), + * and read (under rcu) in packet rx + */ + struct mutex bind_lock; + struct hlist_head binds; + + /* tag allocations. This list is read and updated from atomic contexts, + * but elements are free()ed after a RCU grace-period + */ + spinlock_t keys_lock; + struct hlist_head keys; + /* neighbour table */ struct mutex neigh_lock; struct list_head neighbours; diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c index 58701e6b282c..52bd7f2b78db 100644 --- a/net/mctp/af_mctp.c +++ b/net/mctp/af_mctp.c @@ -18,10 +18,6 @@ /* socket implementation */ -struct mctp_sock { - struct sock sk; -}; - static int mctp_release(struct socket *sock) { struct sock *sk = sock->sk; @@ -36,18 +32,160 @@ static int mctp_release(struct socket *sock) static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen) { - return 0; + struct sock *sk = sock->sk; + struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); + struct sockaddr_mctp *smctp; + int rc; + + if (addrlen < sizeof(*smctp)) + return -EINVAL; + + if (addr->sa_family != AF_MCTP) + return -EAFNOSUPPORT; + + if (!capable(CAP_NET_BIND_SERVICE)) + return -EACCES; + + /* it's a valid sockaddr for MCTP, cast and do protocol checks */ + smctp = (struct sockaddr_mctp *)addr; + + lock_sock(sk); + + /* TODO: allow rebind */ + if (sk_hashed(sk)) { + rc = -EADDRINUSE; + goto out_release; + } + msk->bind_net = smctp->smctp_network; + msk->bind_addr = smctp->smctp_addr.s_addr; + msk->bind_type = smctp->smctp_type & 0x7f; /* ignore the IC bit */ + + rc = sk->sk_prot->hash(sk); + +out_release: + release_sock(sk); + + return rc; } static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { - return 0; + DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name); + const int hlen = MCTP_HEADER_MAXLEN + sizeof(struct mctp_hdr); + int rc, addrlen = msg->msg_namelen; + struct sock *sk = sock->sk; + struct mctp_skb_cb *cb; + struct mctp_route *rt; + struct sk_buff *skb; + + if (addr) { + if (addrlen < sizeof(struct sockaddr_mctp)) + return -EINVAL; + if (addr->smctp_family != AF_MCTP) + return -EINVAL; + if (addr->smctp_tag & ~(MCTP_TAG_MASK | MCTP_TAG_OWNER)) + return -EINVAL; + + } else { + /* TODO: connect()ed sockets */ + return -EDESTADDRREQ; + } + + if (!capable(CAP_NET_RAW)) + return -EACCES; + + rt = mctp_route_lookup(sock_net(sk), addr->smctp_network, + addr->smctp_addr.s_addr); + if (!rt) + return -EHOSTUNREACH; + + skb = sock_alloc_send_skb(sk, hlen + 1 + len, + msg->msg_flags & MSG_DONTWAIT, &rc); + if (!skb) + return rc; + + skb_reserve(skb, hlen); + + /* set type as fist byte in payload */ + *(u8 *)skb_put(skb, 1) = addr->smctp_type; + + rc = memcpy_from_msg((void *)skb_put(skb, len), msg, len); + if (rc < 0) { + kfree_skb(skb); + return rc; + } + + /* set up cb */ + cb = __mctp_cb(skb); + cb->net = addr->smctp_network; + + rc = mctp_local_output(sk, rt, skb, addr->smctp_addr.s_addr, + addr->smctp_tag); + + return rc ? : len; } static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, int flags) { - return 0; + DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name); + struct sock *sk = sock->sk; + struct sk_buff *skb; + size_t msglen; + u8 type; + int rc; + + if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK)) + return -EOPNOTSUPP; + + skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &rc); + if (!skb) + return rc; + + if (!skb->len) { + rc = 0; + goto out_free; + } + + /* extract message type, remove from data */ + type = *((u8 *)skb->data); + msglen = skb->len - 1; + + if (len < msglen) + msg->msg_flags |= MSG_TRUNC; + else + len = msglen; + + rc = skb_copy_datagram_msg(skb, 1, msg, len); + if (rc < 0) + goto out_free; + + sock_recv_ts_and_drops(msg, sk, skb); + + if (addr) { + struct mctp_skb_cb *cb = mctp_cb(skb); + /* TODO: expand mctp_skb_cb for header fields? */ + struct mctp_hdr *hdr = mctp_hdr(skb); + + hdr = mctp_hdr(skb); + addr = msg->msg_name; + addr->smctp_family = AF_MCTP; + addr->smctp_network = cb->net; + addr->smctp_addr.s_addr = hdr->src; + addr->smctp_type = type; + addr->smctp_tag = hdr->flags_seq_tag & + (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO); + msg->msg_namelen = sizeof(*addr); + } + + rc = len; + + if (flags & MSG_TRUNC) + rc = msglen; + +out_free: + skb_free_datagram(sk, skb); + return rc; } static int mctp_setsockopt(struct socket *sock, int level, int optname, @@ -83,16 +221,63 @@ static const struct proto_ops mctp_dgram_ops = { .sendpage = sock_no_sendpage, }; +static int mctp_sk_init(struct sock *sk) +{ + struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); + + INIT_HLIST_HEAD(&msk->keys); + return 0; +} + static void mctp_sk_close(struct sock *sk, long timeout) { sk_common_release(sk); } +static int mctp_sk_hash(struct sock *sk) +{ + struct net *net = sock_net(sk); + + mutex_lock(&net->mctp.bind_lock); + sk_add_node_rcu(sk, &net->mctp.binds); + mutex_unlock(&net->mctp.bind_lock); + + return 0; +} + +static void mctp_sk_unhash(struct sock *sk) +{ + struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); + struct net *net = sock_net(sk); + struct mctp_sk_key *key; + struct hlist_node *tmp; + unsigned long flags; + + /* remove from any type-based binds */ + mutex_lock(&net->mctp.bind_lock); + sk_del_node_init_rcu(sk); + mutex_unlock(&net->mctp.bind_lock); + + /* remove tag allocations */ + spin_lock_irqsave(&net->mctp.keys_lock, flags); + hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) { + hlist_del_rcu(&key->sklist); + hlist_del_rcu(&key->hlist); + kfree_rcu(key, rcu); + } + spin_unlock_irqrestore(&net->mctp.keys_lock, flags); + + synchronize_rcu(); +} + static struct proto mctp_proto = { .name = "MCTP", .owner = THIS_MODULE, .obj_size = sizeof(struct mctp_sock), + .init = mctp_sk_init, .close = mctp_sk_close, + .hash = mctp_sk_hash, + .unhash = mctp_sk_unhash, }; static int mctp_pf_create(struct net *net, struct socket *sock, @@ -147,6 +332,10 @@ static __init int mctp_init(void) { int rc; + /* ensure our uapi tag definitions match the header format */ + BUILD_BUG_ON(MCTP_TAG_OWNER != MCTP_HDR_FLAG_TO); + BUILD_BUG_ON(MCTP_TAG_MASK != MCTP_HDR_TAG_MASK); + pr_info("mctp: management component transport protocol core\n"); rc = sock_register(&mctp_pf); diff --git a/net/mctp/route.c b/net/mctp/route.c index 31568203f9d0..cc9891672eaa 100644 --- a/net/mctp/route.c +++ b/net/mctp/route.c @@ -30,10 +30,139 @@ static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb) return 0; } +static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb) +{ + struct mctp_skb_cb *cb = mctp_cb(skb); + struct mctp_hdr *mh; + struct sock *sk; + u8 type; + + WARN_ON(!rcu_read_lock_held()); + + /* TODO: look up in skb->cb? */ + mh = mctp_hdr(skb); + + if (!skb_headlen(skb)) + return NULL; + + type = (*(u8 *)skb->data) & 0x7f; + + sk_for_each_rcu(sk, &net->mctp.binds) { + struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); + + if (msk->bind_net != MCTP_NET_ANY && msk->bind_net != cb->net) + continue; + + if (msk->bind_type != type) + continue; + + if (msk->bind_addr != MCTP_ADDR_ANY && + msk->bind_addr != mh->dest) + continue; + + return msk; + } + + return NULL; +} + +static bool mctp_key_match(struct mctp_sk_key *key, mctp_eid_t local, + mctp_eid_t peer, u8 tag) +{ + if (key->local_addr != local) + return false; + + if (key->peer_addr != peer) + return false; + + if (key->tag != tag) + return false; + + return true; +} + +static struct mctp_sk_key *mctp_lookup_key(struct net *net, struct sk_buff *skb, + mctp_eid_t peer) +{ + struct mctp_sk_key *key, *ret; + struct mctp_hdr *mh; + u8 tag; + + WARN_ON(!rcu_read_lock_held()); + + mh = mctp_hdr(skb); + tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO); + + ret = NULL; + + hlist_for_each_entry_rcu(key, &net->mctp.keys, hlist) { + if (mctp_key_match(key, mh->dest, peer, tag)) { + ret = key; + break; + } + } + + return ret; +} + static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb) { - /* -> to local stack */ - /* TODO: socket lookup, reassemble */ + struct net *net = dev_net(skb->dev); + struct mctp_sk_key *key; + struct mctp_sock *msk; + struct mctp_hdr *mh; + + msk = NULL; + + /* we may be receiving a locally-routed packet; drop source sk + * accounting + */ + skb_orphan(skb); + + /* ensure we have enough data for a header and a type */ + if (skb->len < sizeof(struct mctp_hdr) + 1) + goto drop; + + /* grab header, advance data ptr */ + mh = mctp_hdr(skb); + skb_pull(skb, sizeof(struct mctp_hdr)); + + if (mh->ver != 1) + goto drop; + + /* TODO: reassembly */ + if ((mh->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM)) + != (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM)) + goto drop; + + rcu_read_lock(); + /* 1. lookup socket matching (src,dest,tag) */ + key = mctp_lookup_key(net, skb, mh->src); + + /* 2. lookup socket macthing (BCAST,dest,tag) */ + if (!key) + key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY); + + /* 3. SOM? -> lookup bound socket, conditionally (!EOM) create + * mapping for future (1)/(2). + */ + if (key) + msk = container_of(key->sk, struct mctp_sock, sk); + else if (!msk && (mh->flags_seq_tag & MCTP_HDR_FLAG_SOM)) + msk = mctp_lookup_bind(net, skb); + + if (!msk) + goto unlock_drop; + + sock_queue_rcv_skb(&msk->sk, skb); + + rcu_read_unlock(); + + return 0; + +unlock_drop: + rcu_read_unlock(); +drop: kfree_skb(skb); return 0; } @@ -91,6 +220,80 @@ static struct mctp_route *mctp_route_alloc(void) return rt; } +/* tag management */ +static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key, + struct mctp_sock *msk) +{ + struct netns_mctp *mns = &net->mctp; + + lockdep_assert_held(&mns->keys_lock); + + key->sk = &msk->sk; + + /* we hold the net->key_lock here, allowing updates to both + * then net and sk + */ + hlist_add_head_rcu(&key->hlist, &mns->keys); + hlist_add_head_rcu(&key->sklist, &msk->keys); +} + +/* Allocate a locally-owned tag value for (saddr, daddr), and reserve + * it for the socket msk + */ +static int mctp_alloc_local_tag(struct mctp_sock *msk, + mctp_eid_t saddr, mctp_eid_t daddr, u8 *tagp) +{ + struct net *net = sock_net(&msk->sk); + struct netns_mctp *mns = &net->mctp; + struct mctp_sk_key *key, *tmp; + unsigned long flags; + int rc = -EAGAIN; + u8 tagbits; + + /* be optimistic, alloc now */ + key = kzalloc(sizeof(*key), GFP_KERNEL); + if (!key) + return -ENOMEM; + key->local_addr = saddr; + key->peer_addr = daddr; + + /* 8 possible tag values */ + tagbits = 0xff; + + spin_lock_irqsave(&mns->keys_lock, flags); + + /* Walk through the existing keys, looking for potential conflicting + * tags. If we find a conflict, clear that bit from tagbits + */ + hlist_for_each_entry(tmp, &mns->keys, hlist) { + /* if we don't own the tag, it can't conflict */ + if (tmp->tag & MCTP_HDR_FLAG_TO) + continue; + + if ((tmp->peer_addr == daddr || + tmp->peer_addr == MCTP_ADDR_ANY) && + tmp->local_addr == saddr) + tagbits &= ~(1 << tmp->tag); + + if (!tagbits) + break; + } + + if (tagbits) { + key->tag = __ffs(tagbits); + mctp_reserve_tag(net, key, msk); + *tagp = key->tag; + rc = 0; + } + + spin_unlock_irqrestore(&mns->keys_lock, flags); + + if (!tagbits) + kfree(key); + + return rc; +} + /* routing lookups */ static bool mctp_rt_match_eid(struct mctp_route *rt, unsigned int net, mctp_eid_t eid) @@ -140,11 +343,13 @@ int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb) int mctp_local_output(struct sock *sk, struct mctp_route *rt, struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag) { + struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); struct mctp_skb_cb *cb = mctp_cb(skb); struct mctp_hdr *hdr; unsigned long flags; mctp_eid_t saddr; int rc; + u8 tag; if (WARN_ON(!rt->dev)) return -EINVAL; @@ -162,6 +367,15 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt, if (rc) return rc; + if (req_tag & MCTP_HDR_FLAG_TO) { + rc = mctp_alloc_local_tag(msk, saddr, daddr, &tag); + if (rc) + return rc; + tag |= MCTP_HDR_FLAG_TO; + } else { + tag = req_tag; + } + /* TODO: we have the route MTU here; packetise */ skb_reset_transport_header(skb); @@ -171,8 +385,10 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt, hdr->ver = 1; hdr->dest = daddr; hdr->src = saddr; - hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM; /* TODO */ + hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM | /* TODO */ + tag; + skb->dev = rt->dev->dev; skb->protocol = htons(ETH_P_MCTP); skb->priority = 0; @@ -529,6 +745,10 @@ static int __net_init mctp_routes_net_init(struct net *net) struct netns_mctp *ns = &net->mctp; INIT_LIST_HEAD(&ns->routes); + INIT_HLIST_HEAD(&ns->binds); + mutex_init(&ns->bind_lock); + INIT_HLIST_HEAD(&ns->keys); + spin_lock_init(&ns->keys_lock); return 0; }