From 60395a20ffd74166ea373ea91418d6f98fa7fdfb Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 3 Mar 2015 17:10:44 -0600 Subject: [PATCH 1/2] neigh: Factor out ___neigh_lookup_noref While looking at the mpls code I found myself writing yet another version of neigh_lookup_noref. We currently have __ipv4_lookup_noref and __ipv6_lookup_noref. So to make my work a little easier and to make it a smidge easier to verify/maintain the mpls code in the future I stopped and wrote ___neigh_lookup_noref. Then I rewote __ipv4_lookup_noref and __ipv6_lookup_noref in terms of this new function. I tested my new version by verifying that the same code is generated in ip_finish_output2 and ip6_finish_output2 where these functions are inlined. To get to ___neigh_lookup_noref I added a new neighbour cache table function key_eq. So that the static size of the key would be available. I also added __neigh_lookup_noref for people who want to to lookup a neighbour table entry quickly but don't know which neibhgour table they are going to look up. Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- include/net/arp.h | 19 ++++----------- include/net/ndisc.h | 19 +-------------- include/net/neighbour.h | 52 +++++++++++++++++++++++++++++++++++++++++ net/core/neighbour.c | 20 ++++------------ net/decnet/dn_neigh.c | 6 +++++ net/ipv4/arp.c | 9 ++++++- net/ipv6/ndisc.c | 7 ++++++ 7 files changed, 83 insertions(+), 49 deletions(-) diff --git a/include/net/arp.h b/include/net/arp.h index 21ee1860abbc..5e0f891d476c 100644 --- a/include/net/arp.h +++ b/include/net/arp.h @@ -9,28 +9,17 @@ extern struct neigh_table arp_tbl; -static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd) +static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 *hash_rnd) { + u32 key = *(const u32 *)pkey; u32 val = key ^ hash32_ptr(dev); - return val * hash_rnd; + return val * hash_rnd[0]; } static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) { - struct neigh_hash_table *nht = rcu_dereference_bh(arp_tbl.nht); - struct neighbour *n; - u32 hash_val; - - hash_val = arp_hashfn(key, dev, nht->hash_rnd[0]) >> (32 - nht->hash_shift); - for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]); - n != NULL; - n = rcu_dereference_bh(n->next)) { - if (n->dev == dev && *(u32 *)n->primary_key == key) - return n; - } - - return NULL; + return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev); } static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key) diff --git a/include/net/ndisc.h b/include/net/ndisc.h index 6bbda34d5e59..b3a7751251b4 100644 --- a/include/net/ndisc.h +++ b/include/net/ndisc.h @@ -156,24 +156,7 @@ static inline u32 ndisc_hashfn(const void *pkey, const struct net_device *dev, _ static inline struct neighbour *__ipv6_neigh_lookup_noref(struct net_device *dev, const void *pkey) { - struct neigh_hash_table *nht; - const u32 *p32 = pkey; - struct neighbour *n; - u32 hash_val; - - nht = rcu_dereference_bh(nd_tbl.nht); - hash_val = ndisc_hashfn(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift); - for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]); - n != NULL; - n = rcu_dereference_bh(n->next)) { - u32 *n32 = (u32 *) n->primary_key; - if (n->dev == dev && - ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) | - (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0) - return n; - } - - return NULL; + return ___neigh_lookup_noref(&nd_tbl, neigh_key_eq128, ndisc_hashfn, pkey, dev); } static inline struct neighbour *__ipv6_neigh_lookup(struct net_device *dev, const void *pkey) diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 9f912e4d4232..14e3f017966b 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -197,6 +197,7 @@ struct neigh_table { __u32 (*hash)(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); + bool (*key_eq)(const struct neighbour *, const void *pkey); int (*constructor)(struct neighbour *); int (*pconstructor)(struct pneigh_entry *); void (*pdestructor)(struct pneigh_entry *); @@ -247,6 +248,57 @@ static inline void *neighbour_priv(const struct neighbour *n) #define NEIGH_UPDATE_F_ISROUTER 0x40000000 #define NEIGH_UPDATE_F_ADMIN 0x80000000 + +static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey) +{ + return *(const u16 *)n->primary_key == *(const u16 *)pkey; +} + +static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey) +{ + return *(const u32 *)n->primary_key == *(const u32 *)pkey; +} + +static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey) +{ + const u32 *n32 = (const u32 *)n->primary_key; + const u32 *p32 = pkey; + + return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) | + (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0; +} + +static inline struct neighbour *___neigh_lookup_noref( + struct neigh_table *tbl, + bool (*key_eq)(const struct neighbour *n, const void *pkey), + __u32 (*hash)(const void *pkey, + const struct net_device *dev, + __u32 *hash_rnd), + const void *pkey, + struct net_device *dev) +{ + struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht); + struct neighbour *n; + u32 hash_val; + + hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift); + for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]); + n != NULL; + n = rcu_dereference_bh(n->next)) { + if (n->dev == dev && key_eq(n, pkey)) + return n; + } + + return NULL; +} + +static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl, + const void *pkey, + struct net_device *dev) +{ + return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev); +} + 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, diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 0f48ea3affed..fe3c6eac5805 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -397,25 +397,15 @@ struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev) { struct neighbour *n; - int key_len = tbl->key_len; - u32 hash_val; - struct neigh_hash_table *nht; NEIGH_CACHE_STAT_INC(tbl, lookups); rcu_read_lock_bh(); - nht = rcu_dereference_bh(tbl->nht); - hash_val = tbl->hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift); - - for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]); - n != NULL; - n = rcu_dereference_bh(n->next)) { - if (dev == n->dev && !memcmp(n->primary_key, pkey, key_len)) { - if (!atomic_inc_not_zero(&n->refcnt)) - n = NULL; - NEIGH_CACHE_STAT_INC(tbl, hits); - break; - } + n = __neigh_lookup_noref(tbl, pkey, dev); + if (n) { + if (!atomic_inc_not_zero(&n->refcnt)) + n = NULL; + NEIGH_CACHE_STAT_INC(tbl, hits); } rcu_read_unlock_bh(); diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c index f123c6c6748c..ee7d1cef0027 100644 --- a/net/decnet/dn_neigh.c +++ b/net/decnet/dn_neigh.c @@ -93,12 +93,18 @@ static u32 dn_neigh_hash(const void *pkey, return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]); } +static bool dn_key_eq(const struct neighbour *neigh, const void *pkey) +{ + return neigh_key_eq16(neigh, pkey); +} + struct neigh_table dn_neigh_table = { .family = PF_DECnet, .entry_size = NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)), .key_len = sizeof(__le16), .protocol = cpu_to_be16(ETH_P_DNA_RT), .hash = dn_neigh_hash, + .key_eq = dn_key_eq, .constructor = dn_neigh_construct, .id = "dn_neigh_cache", .parms ={ diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 6b8aad6a0d7d..5f5c674e130a 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -122,6 +122,7 @@ * Interface to generic neighbour cache. */ static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); +static bool arp_key_eq(const struct neighbour *n, const void *pkey); static int arp_constructor(struct neighbour *neigh); static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); @@ -154,6 +155,7 @@ struct neigh_table arp_tbl = { .key_len = 4, .protocol = cpu_to_be16(ETH_P_IP), .hash = arp_hash, + .key_eq = arp_key_eq, .constructor = arp_constructor, .proxy_redo = parp_redo, .id = "arp_cache", @@ -209,7 +211,12 @@ static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd) { - return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd); + return arp_hashfn(pkey, dev, hash_rnd); +} + +static bool arp_key_eq(const struct neighbour *neigh, const void *pkey) +{ + return neigh_key_eq32(neigh, pkey); } static int arp_constructor(struct neighbour *neigh) diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index e363bbc2420d..247ad7c298f7 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -84,6 +84,7 @@ do { \ static u32 ndisc_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); +static bool ndisc_key_eq(const struct neighbour *neigh, const void *pkey); static int ndisc_constructor(struct neighbour *neigh); static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb); static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb); @@ -119,6 +120,7 @@ struct neigh_table nd_tbl = { .key_len = sizeof(struct in6_addr), .protocol = cpu_to_be16(ETH_P_IPV6), .hash = ndisc_hash, + .key_eq = ndisc_key_eq, .constructor = ndisc_constructor, .pconstructor = pndisc_constructor, .pdestructor = pndisc_destructor, @@ -295,6 +297,11 @@ static u32 ndisc_hash(const void *pkey, return ndisc_hashfn(pkey, dev, hash_rnd); } +static bool ndisc_key_eq(const struct neighbour *n, const void *pkey) +{ + return neigh_key_eq128(n, pkey); +} + static int ndisc_constructor(struct neighbour *neigh) { struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key; From 4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 3 Mar 2015 17:11:16 -0600 Subject: [PATCH 2/2] neigh: Add helper function neigh_xmit For MPLS I am building the code so that either the neighbour mac address can be specified or we can have a next hop in ipv4 or ipv6. The kind of next hop we have is indicated by the neighbour table pointer. A neighbour table pointer of NULL is a link layer address. A non-NULL neighbour table pointer indicates which neighbour table and thus which address family the next hop address is in that we need to look up. The code either sends a packet directly or looks up the appropriate neighbour table entry and sends the packet. Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- include/net/neighbour.h | 3 +++ net/core/neighbour.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 14e3f017966b..afb8237b0a8c 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -358,6 +358,7 @@ void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie); void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *)); +int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *); void pneigh_for_each(struct neigh_table *tbl, void (*cb)(struct pneigh_entry *)); @@ -511,4 +512,6 @@ static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n, memcpy(dst, n->ha, dev->addr_len); } while (read_seqretry(&n->ha_lock, seq)); } + + #endif diff --git a/net/core/neighbour.c b/net/core/neighbour.c index fe3c6eac5805..cffaf00561e7 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -2391,6 +2391,40 @@ void __neigh_for_each_release(struct neigh_table *tbl, } EXPORT_SYMBOL(__neigh_for_each_release); +int neigh_xmit(int family, struct net_device *dev, + const void *addr, struct sk_buff *skb) +{ + int err; + if (family == AF_PACKET) { + err = dev_hard_header(skb, dev, ntohs(skb->protocol), + addr, NULL, skb->len); + if (err < 0) + goto out_kfree_skb; + err = dev_queue_xmit(skb); + } else { + struct neigh_table *tbl; + struct neighbour *neigh; + + err = -ENETDOWN; + tbl = neigh_find_table(family); + if (!tbl) + goto out; + neigh = __neigh_lookup_noref(tbl, addr, dev); + if (!neigh) + neigh = __neigh_create(tbl, addr, dev, false); + err = PTR_ERR(neigh); + if (IS_ERR(neigh)) + goto out_kfree_skb; + err = neigh->output(neigh, skb); + } +out: + return err; +out_kfree_skb: + kfree_skb(skb); + goto out; +} +EXPORT_SYMBOL(neigh_xmit); + #ifdef CONFIG_PROC_FS static struct neighbour *neigh_get_first(struct seq_file *seq)