diff options
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | include/net/mctp.h | 75 | ||||
| -rw-r--r-- | include/net/net_namespace.h | 4 | ||||
| -rw-r--r-- | include/net/netns/mctp.h | 16 | ||||
| -rw-r--r-- | net/mctp/Makefile | 2 | ||||
| -rw-r--r-- | net/mctp/af_mctp.c | 7 | ||||
| -rw-r--r-- | net/mctp/device.c | 8 | ||||
| -rw-r--r-- | net/mctp/route.c | 329 |
8 files changed, 441 insertions, 1 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index c2943c227ee6..4ca73465e690 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11040,6 +11040,7 @@ S: Maintained F: drivers/net/mctp/ F: include/net/mctp.h F: include/net/mctpdevice.h +F: include/net/netns/mctp.h F: net/mctp/ MAN-PAGES: MANUAL PAGES FOR LINUX -- Sections 2, 3, 4, 5, and 7 diff --git a/include/net/mctp.h b/include/net/mctp.h index 61452e03aa85..4094bec5e5db 100644 --- a/include/net/mctp.h +++ b/include/net/mctp.h @@ -11,6 +11,7 @@ #include <linux/bits.h> #include <linux/mctp.h> +#include <net/net_namespace.h> /* MCTP packet definitions */ struct mctp_hdr { @@ -33,6 +34,8 @@ struct mctp_hdr { #define MCTP_HDR_TAG_SHIFT 0 #define MCTP_HDR_TAG_MASK GENMASK(2, 0) +#define MCTP_HEADER_MAXLEN 4 + static inline bool mctp_address_ok(mctp_eid_t eid) { return eid >= 8 && eid < 255; @@ -43,6 +46,78 @@ static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb) return (struct mctp_hdr *)skb_network_header(skb); } +struct mctp_skb_cb { + unsigned int magic; + unsigned int net; + mctp_eid_t src; +}; + +/* skb control-block accessors with a little extra debugging for initial + * development. + * + * TODO: remove checks & mctp_skb_cb->magic; replace callers of __mctp_cb + * with mctp_cb(). + * + * __mctp_cb() is only for the initial ingress code; we should see ->magic set + * at all times after this. + */ +static inline struct mctp_skb_cb *__mctp_cb(struct sk_buff *skb) +{ + struct mctp_skb_cb *cb = (void *)skb->cb; + + cb->magic = 0x4d435450; + return cb; +} + +static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb) +{ + struct mctp_skb_cb *cb = (void *)skb->cb; + + WARN_ON(cb->magic != 0x4d435450); + return (void *)(skb->cb); +} + +/* Route definition. + * + * These are held in the pernet->mctp.routes list, with RCU protection for + * removed routes. We hold a reference to the netdev; routes need to be + * dropped on NETDEV_UNREGISTER events. + * + * Updates to the route table are performed under rtnl; all reads under RCU, + * so routes cannot be referenced over a RCU grace period. Specifically: A + * caller cannot block between mctp_route_lookup and passing the route to + * mctp_do_route. + */ +struct mctp_route { + mctp_eid_t min, max; + + struct mctp_dev *dev; + unsigned int mtu; + int (*output)(struct mctp_route *route, + struct sk_buff *skb); + + struct list_head list; + refcount_t refs; + struct rcu_head rcu; +}; + +/* route interfaces */ +struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet, + mctp_eid_t daddr); + +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); + +/* routing <--> device interface */ +int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr); +int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr); +void mctp_route_remove_dev(struct mctp_dev *mdev); + +int mctp_routes_init(void); +void mctp_routes_exit(void); + void mctp_device_init(void); void mctp_device_exit(void); diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 12cf6d7ea62c..cc54750dd3db 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -34,6 +34,7 @@ #include <net/netns/xdp.h> #include <net/netns/smc.h> #include <net/netns/bpf.h> +#include <net/netns/mctp.h> #include <linux/ns_common.h> #include <linux/idr.h> #include <linux/skbuff.h> @@ -167,6 +168,9 @@ struct net { #ifdef CONFIG_XDP_SOCKETS struct netns_xdp xdp; #endif +#if IS_ENABLED(CONFIG_MCTP) + struct netns_mctp mctp; +#endif #if IS_ENABLED(CONFIG_CRYPTO_USER) struct sock *crypto_nlsk; #endif diff --git a/include/net/netns/mctp.h b/include/net/netns/mctp.h new file mode 100644 index 000000000000..508459b08a59 --- /dev/null +++ b/include/net/netns/mctp.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * MCTP per-net structures + */ + +#ifndef __NETNS_MCTP_H__ +#define __NETNS_MCTP_H__ + +#include <linux/types.h> + +struct netns_mctp { + /* Only updated under RTNL, entries freed via RCU */ + struct list_head routes; +}; + +#endif /* __NETNS_MCTP_H__ */ diff --git a/net/mctp/Makefile b/net/mctp/Makefile index 2ea98c27b262..b1a330e9d82a 100644 --- a/net/mctp/Makefile +++ b/net/mctp/Makefile @@ -1,3 +1,3 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_MCTP) += mctp.o -mctp-objs := af_mctp.o device.o +mctp-objs := af_mctp.o device.o route.o diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c index 401b4fa141a5..8085f5912101 100644 --- a/net/mctp/af_mctp.c +++ b/net/mctp/af_mctp.c @@ -157,10 +157,16 @@ static __init int mctp_init(void) if (rc) goto err_unreg_sock; + rc = mctp_routes_init(); + if (rc) + goto err_unreg_proto; + mctp_device_init(); return 0; +err_unreg_proto: + proto_unregister(&mctp_proto); err_unreg_sock: sock_unregister(PF_MCTP); @@ -170,6 +176,7 @@ err_unreg_sock: static __exit void mctp_exit(void) { mctp_device_exit(); + mctp_routes_exit(); proto_unregister(&mctp_proto); sock_unregister(PF_MCTP); } diff --git a/net/mctp/device.c b/net/mctp/device.c index 877abe5312cd..5f1b18c17351 100644 --- a/net/mctp/device.c +++ b/net/mctp/device.c @@ -197,6 +197,8 @@ static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, kfree(tmp_addrs); + mctp_route_add_local(mdev, addr->s_addr); + return 0; } @@ -240,6 +242,11 @@ static int mctp_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, if (!pos) return -ENOENT; + rc = mctp_route_remove_local(mdev, addr->s_addr); + // we can ignore -ENOENT in the case a route was already removed + if (rc < 0 && rc != -ENOENT) + return rc; + spin_lock_irqsave(&mdev->addrs_lock, flags); memmove(pos, pos + 1, mdev->num_addrs - 1 - (pos - mdev->addrs)); mdev->num_addrs--; @@ -334,6 +341,7 @@ static void mctp_unregister(struct net_device *dev) RCU_INIT_POINTER(mdev->dev->mctp_ptr, NULL); + mctp_route_remove_dev(mdev); kfree(mdev->addrs); mctp_dev_destroy(mdev); diff --git a/net/mctp/route.c b/net/mctp/route.c new file mode 100644 index 000000000000..2bcc13175a9e --- /dev/null +++ b/net/mctp/route.c @@ -0,0 +1,329 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Management Component Transport Protocol (MCTP) - routing + * implementation. + * + * This is currently based on a simple routing table, with no dst cache. The + * number of routes should stay fairly small, so the lookup cost is small. + * + * Copyright (c) 2021 Code Construct + * Copyright (c) 2021 Google + */ + +#include <linux/idr.h> +#include <linux/mctp.h> +#include <linux/netdevice.h> +#include <linux/rtnetlink.h> +#include <linux/skbuff.h> + +#include <uapi/linux/if_arp.h> + +#include <net/mctp.h> +#include <net/mctpdevice.h> + +/* route output callbacks */ +static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb) +{ + kfree_skb(skb); + return 0; +} + +static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb) +{ + /* -> to local stack */ + /* TODO: socket lookup, reassemble */ + kfree_skb(skb); + return 0; +} + +static int __always_unused mctp_route_output(struct mctp_route *route, + struct sk_buff *skb) +{ + unsigned int mtu; + int rc; + + skb->protocol = htons(ETH_P_MCTP); + + mtu = READ_ONCE(skb->dev->mtu); + if (skb->len > mtu) { + kfree_skb(skb); + return -EMSGSIZE; + } + + /* TODO: daddr (from rt->neigh), saddr (from device?) */ + rc = dev_hard_header(skb, skb->dev, ntohs(skb->protocol), + NULL, NULL, skb->len); + if (rc) { + kfree_skb(skb); + return -EHOSTUNREACH; + } + + rc = dev_queue_xmit(skb); + if (rc) + rc = net_xmit_errno(rc); + + return rc; +} + +/* route alloc/release */ +static void mctp_route_release(struct mctp_route *rt) +{ + if (refcount_dec_and_test(&rt->refs)) { + dev_put(rt->dev->dev); + kfree_rcu(rt, rcu); + } +} + +/* returns a route with the refcount at 1 */ +static struct mctp_route *mctp_route_alloc(void) +{ + struct mctp_route *rt; + + rt = kzalloc(sizeof(*rt), GFP_KERNEL); + if (!rt) + return NULL; + + INIT_LIST_HEAD(&rt->list); + refcount_set(&rt->refs, 1); + rt->output = mctp_route_discard; + + return rt; +} + +/* routing lookups */ +static bool mctp_rt_match_eid(struct mctp_route *rt, + unsigned int net, mctp_eid_t eid) +{ + return READ_ONCE(rt->dev->net) == net && + rt->min <= eid && rt->max >= eid; +} + +/* compares match, used for duplicate prevention */ +static bool mctp_rt_compare_exact(struct mctp_route *rt1, + struct mctp_route *rt2) +{ + ASSERT_RTNL(); + return rt1->dev->net == rt2->dev->net && + rt1->min == rt2->min && + rt1->max == rt2->max; +} + +struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet, + mctp_eid_t daddr) +{ + struct mctp_route *tmp, *rt = NULL; + + list_for_each_entry_rcu(tmp, &net->mctp.routes, list) { + /* TODO: add metrics */ + if (mctp_rt_match_eid(tmp, dnet, daddr)) { + if (refcount_inc_not_zero(&tmp->refs)) { + rt = tmp; + break; + } + } + } + + return rt; +} + +/* sends a skb to rt and releases the route. */ +int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb) +{ + int rc; + + rc = rt->output(rt, skb); + mctp_route_release(rt); + return rc; +} + +int mctp_local_output(struct sock *sk, struct mctp_route *rt, + struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag) +{ + struct mctp_skb_cb *cb = mctp_cb(skb); + struct mctp_hdr *hdr; + unsigned long flags; + mctp_eid_t saddr; + int rc; + + if (WARN_ON(!rt->dev)) + return -EINVAL; + + spin_lock_irqsave(&rt->dev->addrs_lock, flags); + if (rt->dev->num_addrs == 0) { + rc = -EHOSTUNREACH; + } else { + /* use the outbound interface's first address as our source */ + saddr = rt->dev->addrs[0]; + rc = 0; + } + spin_unlock_irqrestore(&rt->dev->addrs_lock, flags); + + if (rc) + return rc; + + /* TODO: we have the route MTU here; packetise */ + + skb_reset_transport_header(skb); + skb_push(skb, sizeof(struct mctp_hdr)); + skb_reset_network_header(skb); + hdr = mctp_hdr(skb); + hdr->ver = 1; + hdr->dest = daddr; + hdr->src = saddr; + hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM; /* TODO */ + + skb->protocol = htons(ETH_P_MCTP); + skb->priority = 0; + + /* cb->net will have been set on initial ingress */ + cb->src = saddr; + + return mctp_do_route(rt, skb); +} + +/* route management */ +int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr) +{ + struct net *net = dev_net(mdev->dev); + struct mctp_route *rt, *ert; + + rt = mctp_route_alloc(); + if (!rt) + return -ENOMEM; + + rt->min = addr; + rt->max = addr; + rt->dev = mdev; + dev_hold(rt->dev->dev); + rt->output = mctp_route_input; + + ASSERT_RTNL(); + /* Prevent duplicate identical routes. */ + list_for_each_entry(ert, &net->mctp.routes, list) { + if (mctp_rt_compare_exact(rt, ert)) { + mctp_route_release(rt); + return -EEXIST; + } + } + + list_add_rcu(&rt->list, &net->mctp.routes); + + return 0; +} + +int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr) +{ + struct net *net = dev_net(mdev->dev); + struct mctp_route *rt, *tmp; + + ASSERT_RTNL(); + + list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) { + if (rt->dev == mdev && rt->min == addr && rt->max == addr) { + list_del_rcu(&rt->list); + /* TODO: immediate RTM_DELROUTE */ + mctp_route_release(rt); + } + } + + return 0; +} + +/* removes all entries for a given device */ +void mctp_route_remove_dev(struct mctp_dev *mdev) +{ + struct net *net = dev_net(mdev->dev); + struct mctp_route *rt, *tmp; + + ASSERT_RTNL(); + list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) { + if (rt->dev == mdev) { + list_del_rcu(&rt->list); + /* TODO: immediate RTM_DELROUTE */ + mctp_route_release(rt); + } + } +} + +/* Incoming packet-handling */ + +static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev, + struct packet_type *pt, + struct net_device *orig_dev) +{ + struct net *net = dev_net(dev); + struct mctp_skb_cb *cb; + struct mctp_route *rt; + struct mctp_hdr *mh; + + /* basic non-data sanity checks */ + if (dev->type != ARPHRD_MCTP) + goto err_drop; + + if (!pskb_may_pull(skb, sizeof(struct mctp_hdr))) + goto err_drop; + + skb_reset_transport_header(skb); + skb_reset_network_header(skb); + + /* We have enough for a header; decode and route */ + mh = mctp_hdr(skb); + if (mh->ver < MCTP_VER_MIN || mh->ver > MCTP_VER_MAX) + goto err_drop; + + cb = __mctp_cb(skb); + rcu_read_lock(); + cb->net = READ_ONCE(__mctp_dev_get(dev)->net); + rcu_read_unlock(); + + rt = mctp_route_lookup(net, cb->net, mh->dest); + if (!rt) + goto err_drop; + + mctp_do_route(rt, skb); + + return NET_RX_SUCCESS; + +err_drop: + kfree_skb(skb); + return NET_RX_DROP; +} + +static struct packet_type mctp_packet_type = { + .type = cpu_to_be16(ETH_P_MCTP), + .func = mctp_pkttype_receive, +}; + +/* net namespace implementation */ +static int __net_init mctp_routes_net_init(struct net *net) +{ + struct netns_mctp *ns = &net->mctp; + + INIT_LIST_HEAD(&ns->routes); + return 0; +} + +static void __net_exit mctp_routes_net_exit(struct net *net) +{ + struct mctp_route *rt; + + list_for_each_entry_rcu(rt, &net->mctp.routes, list) + mctp_route_release(rt); +} + +static struct pernet_operations mctp_net_ops = { + .init = mctp_routes_net_init, + .exit = mctp_routes_net_exit, +}; + +int __init mctp_routes_init(void) +{ + dev_add_pack(&mctp_packet_type); + return register_pernet_subsys(&mctp_net_ops); +} + +void __exit mctp_routes_exit(void) +{ + unregister_pernet_subsys(&mctp_net_ops); + dev_remove_pack(&mctp_packet_type); +} |