From d7480fd3b1738a8eae6a76098b17af318cf9b9cc Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Mon, 10 Nov 2014 15:59:36 -0800 Subject: [PATCH] neigh: remove dynamic neigh table registration support Currently there are only three neigh tables in the whole kernel: arp table, ndisc table and decnet neigh table. What's more, we don't support registering multiple tables per family. Therefore we can just make these tables statically built-in. Cc: David S. Miller Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- include/net/neighbour.h | 11 +- net/core/neighbour.c | 247 ++++++++++++++++++---------------------- net/decnet/dn_neigh.c | 4 +- net/ipv4/arp.c | 2 +- net/ipv6/ndisc.c | 4 +- 5 files changed, 126 insertions(+), 142 deletions(-) diff --git a/include/net/neighbour.h b/include/net/neighbour.h index dedfb188b1a7..eb070b3674a1 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -220,6 +220,13 @@ struct neigh_table { struct pneigh_entry **phash_buckets; }; +enum { + NEIGH_ARP_TABLE = 0, + NEIGH_ND_TABLE = 1, + NEIGH_DN_TABLE = 2, + NEIGH_NR_TABLES, +}; + static inline int neigh_parms_family(struct neigh_parms *p) { return p->tbl->family; @@ -240,8 +247,8 @@ static inline void *neighbour_priv(const struct neighbour *n) #define NEIGH_UPDATE_F_ISROUTER 0x40000000 #define NEIGH_UPDATE_F_ADMIN 0x80000000 -void neigh_table_init(struct neigh_table *tbl); -int neigh_table_clear(struct neigh_table *tbl); +void neigh_table_init(int index, struct neigh_table *tbl); +int neigh_table_clear(int index, struct neigh_table *tbl); struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev); struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net, diff --git a/net/core/neighbour.c b/net/core/neighbour.c index edd04116ecb7..8e38f17288d3 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -56,7 +56,6 @@ static void __neigh_notify(struct neighbour *n, int type, int flags); static void neigh_update_notify(struct neighbour *neigh); static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev); -static struct neigh_table *neigh_tables; #ifdef CONFIG_PROC_FS static const struct file_operations neigh_stat_seq_fops; #endif @@ -87,13 +86,8 @@ static const struct file_operations neigh_stat_seq_fops; the most complicated procedure, which we allow is dev->hard_header. It is supposed, that dev->hard_header is simplistic and does not make callbacks to neighbour tables. - - The last lock is neigh_tbl_lock. It is pure SMP lock, protecting - list of neighbour tables. This list is used only in process context, */ -static DEFINE_RWLOCK(neigh_tbl_lock); - static int neigh_blackhole(struct neighbour *neigh, struct sk_buff *skb) { kfree_skb(skb); @@ -1520,7 +1514,9 @@ static void neigh_parms_destroy(struct neigh_parms *parms) static struct lock_class_key neigh_table_proxy_queue_class; -static void neigh_table_init_no_netlink(struct neigh_table *tbl) +static struct neigh_table *neigh_tables[NEIGH_NR_TABLES] __read_mostly; + +void neigh_table_init(int index, struct neigh_table *tbl) { unsigned long now = jiffies; unsigned long phsize; @@ -1566,34 +1562,14 @@ static void neigh_table_init_no_netlink(struct neigh_table *tbl) tbl->last_flush = now; tbl->last_rand = now + tbl->parms.reachable_time * 20; -} - -void neigh_table_init(struct neigh_table *tbl) -{ - struct neigh_table *tmp; - neigh_table_init_no_netlink(tbl); - write_lock(&neigh_tbl_lock); - for (tmp = neigh_tables; tmp; tmp = tmp->next) { - if (tmp->family == tbl->family) - break; - } - tbl->next = neigh_tables; - neigh_tables = tbl; - write_unlock(&neigh_tbl_lock); - - if (unlikely(tmp)) { - pr_err("Registering multiple tables for family %d\n", - tbl->family); - dump_stack(); - } + neigh_tables[index] = tbl; } EXPORT_SYMBOL(neigh_table_init); -int neigh_table_clear(struct neigh_table *tbl) +int neigh_table_clear(int index, struct neigh_table *tbl) { - struct neigh_table **tp; - + neigh_tables[index] = NULL; /* It is not clean... Fix it to unload IPv6 module safely */ cancel_delayed_work_sync(&tbl->gc_work); del_timer_sync(&tbl->proxy_timer); @@ -1601,14 +1577,6 @@ int neigh_table_clear(struct neigh_table *tbl) neigh_ifdown(tbl, NULL); if (atomic_read(&tbl->entries)) pr_crit("neighbour leakage\n"); - write_lock(&neigh_tbl_lock); - for (tp = &neigh_tables; *tp; tp = &(*tp)->next) { - if (*tp == tbl) { - *tp = tbl->next; - break; - } - } - write_unlock(&neigh_tbl_lock); call_rcu(&rcu_dereference_protected(tbl->nht, 1)->rcu, neigh_hash_free_rcu); @@ -1626,12 +1594,32 @@ int neigh_table_clear(struct neigh_table *tbl) } EXPORT_SYMBOL(neigh_table_clear); +static struct neigh_table *neigh_find_table(int family) +{ + struct neigh_table *tbl = NULL; + + switch (family) { + case AF_INET: + tbl = neigh_tables[NEIGH_ARP_TABLE]; + break; + case AF_INET6: + tbl = neigh_tables[NEIGH_ND_TABLE]; + break; + case AF_DECnet: + tbl = neigh_tables[NEIGH_DN_TABLE]; + break; + } + + return tbl; +} + static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh) { struct net *net = sock_net(skb->sk); struct ndmsg *ndm; struct nlattr *dst_attr; struct neigh_table *tbl; + struct neighbour *neigh; struct net_device *dev = NULL; int err = -EINVAL; @@ -1652,39 +1640,31 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh) } } - read_lock(&neigh_tbl_lock); - for (tbl = neigh_tables; tbl; tbl = tbl->next) { - struct neighbour *neigh; - - if (tbl->family != ndm->ndm_family) - continue; - read_unlock(&neigh_tbl_lock); - - if (nla_len(dst_attr) < tbl->key_len) - goto out; + tbl = neigh_find_table(ndm->ndm_family); + if (tbl == NULL) + return -EAFNOSUPPORT; - if (ndm->ndm_flags & NTF_PROXY) { - err = pneigh_delete(tbl, net, nla_data(dst_attr), dev); - goto out; - } + if (nla_len(dst_attr) < tbl->key_len) + goto out; - if (dev == NULL) - goto out; + if (ndm->ndm_flags & NTF_PROXY) { + err = pneigh_delete(tbl, net, nla_data(dst_attr), dev); + goto out; + } - neigh = neigh_lookup(tbl, nla_data(dst_attr), dev); - if (neigh == NULL) { - err = -ENOENT; - goto out; - } + if (dev == NULL) + goto out; - err = neigh_update(neigh, NULL, NUD_FAILED, - NEIGH_UPDATE_F_OVERRIDE | - NEIGH_UPDATE_F_ADMIN); - neigh_release(neigh); + neigh = neigh_lookup(tbl, nla_data(dst_attr), dev); + if (neigh == NULL) { + err = -ENOENT; goto out; } - read_unlock(&neigh_tbl_lock); - err = -EAFNOSUPPORT; + + err = neigh_update(neigh, NULL, NUD_FAILED, + NEIGH_UPDATE_F_OVERRIDE | + NEIGH_UPDATE_F_ADMIN); + neigh_release(neigh); out: return err; @@ -1692,11 +1672,14 @@ out: static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh) { + int flags = NEIGH_UPDATE_F_ADMIN | NEIGH_UPDATE_F_OVERRIDE; struct net *net = sock_net(skb->sk); struct ndmsg *ndm; struct nlattr *tb[NDA_MAX+1]; struct neigh_table *tbl; struct net_device *dev = NULL; + struct neighbour *neigh; + void *dst, *lladdr; int err; ASSERT_RTNL(); @@ -1720,70 +1703,60 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh) goto out; } - read_lock(&neigh_tbl_lock); - for (tbl = neigh_tables; tbl; tbl = tbl->next) { - int flags = NEIGH_UPDATE_F_ADMIN | NEIGH_UPDATE_F_OVERRIDE; - struct neighbour *neigh; - void *dst, *lladdr; + tbl = neigh_find_table(ndm->ndm_family); + if (tbl == NULL) + return -EAFNOSUPPORT; - if (tbl->family != ndm->ndm_family) - continue; - read_unlock(&neigh_tbl_lock); + if (nla_len(tb[NDA_DST]) < tbl->key_len) + goto out; + dst = nla_data(tb[NDA_DST]); + lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL; - if (nla_len(tb[NDA_DST]) < tbl->key_len) - goto out; - dst = nla_data(tb[NDA_DST]); - lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL; + if (ndm->ndm_flags & NTF_PROXY) { + struct pneigh_entry *pn; + + err = -ENOBUFS; + pn = pneigh_lookup(tbl, net, dst, dev, 1); + if (pn) { + pn->flags = ndm->ndm_flags; + err = 0; + } + goto out; + } - if (ndm->ndm_flags & NTF_PROXY) { - struct pneigh_entry *pn; + if (dev == NULL) + goto out; - err = -ENOBUFS; - pn = pneigh_lookup(tbl, net, dst, dev, 1); - if (pn) { - pn->flags = ndm->ndm_flags; - err = 0; - } + neigh = neigh_lookup(tbl, dst, dev); + if (neigh == NULL) { + if (!(nlh->nlmsg_flags & NLM_F_CREATE)) { + err = -ENOENT; goto out; } - if (dev == NULL) + neigh = __neigh_lookup_errno(tbl, dst, dev); + if (IS_ERR(neigh)) { + err = PTR_ERR(neigh); + goto out; + } + } else { + if (nlh->nlmsg_flags & NLM_F_EXCL) { + err = -EEXIST; + neigh_release(neigh); goto out; - - neigh = neigh_lookup(tbl, dst, dev); - if (neigh == NULL) { - if (!(nlh->nlmsg_flags & NLM_F_CREATE)) { - err = -ENOENT; - goto out; - } - - neigh = __neigh_lookup_errno(tbl, dst, dev); - if (IS_ERR(neigh)) { - err = PTR_ERR(neigh); - goto out; - } - } else { - if (nlh->nlmsg_flags & NLM_F_EXCL) { - err = -EEXIST; - neigh_release(neigh); - goto out; - } - - if (!(nlh->nlmsg_flags & NLM_F_REPLACE)) - flags &= ~NEIGH_UPDATE_F_OVERRIDE; } - if (ndm->ndm_flags & NTF_USE) { - neigh_event_send(neigh, NULL); - err = 0; - } else - err = neigh_update(neigh, lladdr, ndm->ndm_state, flags); - neigh_release(neigh); - goto out; + if (!(nlh->nlmsg_flags & NLM_F_REPLACE)) + flags &= ~NEIGH_UPDATE_F_OVERRIDE; } - read_unlock(&neigh_tbl_lock); - err = -EAFNOSUPPORT; + if (ndm->ndm_flags & NTF_USE) { + neigh_event_send(neigh, NULL); + err = 0; + } else + err = neigh_update(neigh, lladdr, ndm->ndm_state, flags); + neigh_release(neigh); + out: return err; } @@ -1982,7 +1955,8 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh) struct neigh_table *tbl; struct ndtmsg *ndtmsg; struct nlattr *tb[NDTA_MAX+1]; - int err; + bool found = false; + int err, tidx; err = nlmsg_parse(nlh, sizeof(*ndtmsg), tb, NDTA_MAX, nl_neightbl_policy); @@ -1995,19 +1969,21 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh) } ndtmsg = nlmsg_data(nlh); - read_lock(&neigh_tbl_lock); - for (tbl = neigh_tables; tbl; tbl = tbl->next) { + + for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) { + tbl = neigh_tables[tidx]; + if (!tbl) + continue; if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family) continue; - - if (nla_strcmp(tb[NDTA_NAME], tbl->id) == 0) + if (nla_strcmp(tb[NDTA_NAME], tbl->id) == 0) { + found = true; break; + } } - if (tbl == NULL) { - err = -ENOENT; - goto errout_locked; - } + if (!found) + return -ENOENT; /* * We acquire tbl->lock to be nice to the periodic timers and @@ -2118,8 +2094,6 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh) errout_tbl_lock: write_unlock_bh(&tbl->lock); -errout_locked: - read_unlock(&neigh_tbl_lock); errout: return err; } @@ -2134,10 +2108,13 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb) family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family; - read_lock(&neigh_tbl_lock); - for (tbl = neigh_tables, tidx = 0; tbl; tbl = tbl->next, tidx++) { + for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) { struct neigh_parms *p; + tbl = neigh_tables[tidx]; + if (!tbl) + continue; + if (tidx < tbl_skip || (family && tbl->family != family)) continue; @@ -2168,7 +2145,6 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb) neigh_skip = 0; } out: - read_unlock(&neigh_tbl_lock); cb->args[0] = tidx; cb->args[1] = nidx; @@ -2351,7 +2327,6 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb) int proxy = 0; int err; - read_lock(&neigh_tbl_lock); family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family; /* check for full ndmsg structure presence, family member is @@ -2363,8 +2338,11 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb) s_t = cb->args[0]; - for (tbl = neigh_tables, t = 0; tbl; - tbl = tbl->next, t++) { + for (t = 0; t < NEIGH_NR_TABLES; t++) { + tbl = neigh_tables[t]; + + if (!tbl) + continue; if (t < s_t || (family && tbl->family != family)) continue; if (t > s_t) @@ -2377,7 +2355,6 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb) if (err < 0) break; } - read_unlock(&neigh_tbl_lock); cb->args[0] = t; return skb->len; diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c index c8121ceddb9e..7ca7c3143da3 100644 --- a/net/decnet/dn_neigh.c +++ b/net/decnet/dn_neigh.c @@ -591,7 +591,7 @@ static const struct file_operations dn_neigh_seq_fops = { void __init dn_neigh_init(void) { - neigh_table_init(&dn_neigh_table); + neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table); proc_create("decnet_neigh", S_IRUGO, init_net.proc_net, &dn_neigh_seq_fops); } @@ -599,5 +599,5 @@ void __init dn_neigh_init(void) void __exit dn_neigh_cleanup(void) { remove_proc_entry("decnet_neigh", init_net.proc_net); - neigh_table_clear(&dn_neigh_table); + neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table); } diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 16acb59d665e..205e1472aa78 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -1292,7 +1292,7 @@ static int arp_proc_init(void); void __init arp_init(void) { - neigh_table_init(&arp_tbl); + neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl); dev_add_pack(&arp_packet_type); arp_proc_init(); diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 4cb45c1079a2..2c9f6bf57325 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1763,7 +1763,7 @@ int __init ndisc_init(void) /* * Initialize the neighbour table */ - neigh_table_init(&nd_tbl); + neigh_table_init(NEIGH_ND_TABLE, &nd_tbl); #ifdef CONFIG_SYSCTL err = neigh_sysctl_register(NULL, &nd_tbl.parms, @@ -1796,6 +1796,6 @@ void ndisc_cleanup(void) #ifdef CONFIG_SYSCTL neigh_sysctl_unregister(&nd_tbl.parms); #endif - neigh_table_clear(&nd_tbl); + neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl); unregister_pernet_subsys(&ndisc_net_ops); } -- 2.20.1