diff options
Diffstat (limited to 'net/core/flow_dissector.c')
| -rw-r--r-- | net/core/flow_dissector.c | 155 |
1 files changed, 117 insertions, 38 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 68eda10d0680..ca871657a4c4 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -114,19 +114,50 @@ int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, { struct bpf_prog *attached; struct net *net; + int ret = 0; net = current->nsproxy->net_ns; mutex_lock(&flow_dissector_mutex); + + if (net == &init_net) { + /* BPF flow dissector in the root namespace overrides + * any per-net-namespace one. When attaching to root, + * make sure we don't have any BPF program attached + * to the non-root namespaces. + */ + struct net *ns; + + for_each_net(ns) { + if (ns == &init_net) + continue; + if (rcu_access_pointer(ns->flow_dissector_prog)) { + ret = -EEXIST; + goto out; + } + } + } else { + /* Make sure root flow dissector is not attached + * when attaching to the non-root namespace. + */ + if (rcu_access_pointer(init_net.flow_dissector_prog)) { + ret = -EEXIST; + goto out; + } + } + attached = rcu_dereference_protected(net->flow_dissector_prog, lockdep_is_held(&flow_dissector_mutex)); - if (attached) { - /* Only one BPF program can be attached at a time */ - mutex_unlock(&flow_dissector_mutex); - return -EEXIST; + if (attached == prog) { + /* The same program cannot be attached twice */ + ret = -EINVAL; + goto out; } rcu_assign_pointer(net->flow_dissector_prog, prog); + if (attached) + bpf_prog_put(attached); +out: mutex_unlock(&flow_dissector_mutex); - return 0; + return ret; } int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr) @@ -147,27 +178,6 @@ int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr) mutex_unlock(&flow_dissector_mutex); return 0; } -/** - * skb_flow_get_be16 - extract be16 entity - * @skb: sk_buff to extract from - * @poff: offset to extract at - * @data: raw buffer pointer to the packet - * @hlen: packet header length - * - * The function will try to retrieve a be32 entity at - * offset poff - */ -static __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff, - void *data, int hlen) -{ - __be16 *u, _u; - - u = __skb_header_pointer(skb, poff, sizeof(_u), data, hlen, &_u); - if (u) - return *u; - - return 0; -} /** * __skb_flow_get_ports - extract the upper layer ports and return them @@ -203,6 +213,72 @@ __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, } EXPORT_SYMBOL(__skb_flow_get_ports); +static bool icmp_has_id(u8 type) +{ + switch (type) { + case ICMP_ECHO: + case ICMP_ECHOREPLY: + case ICMP_TIMESTAMP: + case ICMP_TIMESTAMPREPLY: + case ICMPV6_ECHO_REQUEST: + case ICMPV6_ECHO_REPLY: + return true; + } + + return false; +} + +/** + * skb_flow_get_icmp_tci - extract ICMP(6) Type, Code and Identifier fields + * @skb: sk_buff to extract from + * @key_icmp: struct flow_dissector_key_icmp to fill + * @data: raw buffer pointer to the packet + * @toff: offset to extract at + * @hlen: packet header length + */ +void skb_flow_get_icmp_tci(const struct sk_buff *skb, + struct flow_dissector_key_icmp *key_icmp, + void *data, int thoff, int hlen) +{ + struct icmphdr *ih, _ih; + + ih = __skb_header_pointer(skb, thoff, sizeof(_ih), data, hlen, &_ih); + if (!ih) + return; + + key_icmp->type = ih->type; + key_icmp->code = ih->code; + + /* As we use 0 to signal that the Id field is not present, + * avoid confusion with packets without such field + */ + if (icmp_has_id(ih->type)) + key_icmp->id = ih->un.echo.id ? : 1; + else + key_icmp->id = 0; +} +EXPORT_SYMBOL(skb_flow_get_icmp_tci); + +/* If FLOW_DISSECTOR_KEY_ICMP is set, dissect an ICMP packet + * using skb_flow_get_icmp_tci(). + */ +static void __skb_flow_dissect_icmp(const struct sk_buff *skb, + struct flow_dissector *flow_dissector, + void *target_container, + void *data, int thoff, int hlen) +{ + struct flow_dissector_key_icmp *key_icmp; + + if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ICMP)) + return; + + key_icmp = skb_flow_dissector_target(flow_dissector, + FLOW_DISSECTOR_KEY_ICMP, + target_container); + + skb_flow_get_icmp_tci(skb, key_icmp, data, thoff, hlen); +} + void skb_flow_dissect_meta(const struct sk_buff *skb, struct flow_dissector *flow_dissector, void *target_container) @@ -853,7 +929,6 @@ bool __skb_flow_dissect(const struct net *net, struct flow_dissector_key_basic *key_basic; struct flow_dissector_key_addrs *key_addrs; struct flow_dissector_key_ports *key_ports; - struct flow_dissector_key_icmp *key_icmp; struct flow_dissector_key_tags *key_tags; struct flow_dissector_key_vlan *key_vlan; struct bpf_prog *attached = NULL; @@ -910,7 +985,10 @@ bool __skb_flow_dissect(const struct net *net, WARN_ON_ONCE(!net); if (net) { rcu_read_lock(); - attached = rcu_dereference(net->flow_dissector_prog); + attached = rcu_dereference(init_net.flow_dissector_prog); + + if (!attached) + attached = rcu_dereference(net->flow_dissector_prog); if (attached) { struct bpf_flow_keys flow_keys; @@ -1295,6 +1373,12 @@ ip_proto_again: data, nhoff, hlen); break; + case IPPROTO_ICMP: + case IPPROTO_ICMPV6: + __skb_flow_dissect_icmp(skb, flow_dissector, target_container, + data, nhoff, hlen); + break; + default: break; } @@ -1308,14 +1392,6 @@ ip_proto_again: data, hlen); } - if (dissector_uses_key(flow_dissector, - FLOW_DISSECTOR_KEY_ICMP)) { - key_icmp = skb_flow_dissector_target(flow_dissector, - FLOW_DISSECTOR_KEY_ICMP, - target_container); - key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen); - } - /* Process result of IP proto processing */ switch (fdret) { case FLOW_DISSECT_RET_PROTO_AGAIN: @@ -1365,8 +1441,8 @@ static const void *flow_keys_hash_start(const struct flow_keys *flow) static inline size_t flow_keys_hash_length(const struct flow_keys *flow) { size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs); - BUILD_BUG_ON(offsetof(typeof(*flow), addrs) != - sizeof(*flow) - sizeof(flow->addrs)); + + BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32)); switch (flow->control.addr_type) { case FLOW_DISSECTOR_KEY_IPV4_ADDRS: @@ -1412,6 +1488,9 @@ __be32 flow_get_u32_dst(const struct flow_keys *flow) } EXPORT_SYMBOL(flow_get_u32_dst); +/* Sort the source and destination IP (and the ports if the IP are the same), + * to have consistent hash within the two directions + */ static inline void __flow_hash_consistentify(struct flow_keys *keys) { int addr_diff, i; |