X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=datapath%2Fflow.c;h=face40b3c9f4e4da96a0587c005db4ac8fd56502;hb=cd10ed7fb4fb5b1e3ed8e3fae1fd115c7ae96e77;hp=f769b14d6abc9244d2a6a75d3cd4e545a980f7ec;hpb=50f06e1642e246bb9969035c9e3db7c44e7b95e0;p=openvswitch diff --git a/datapath/flow.c b/datapath/flow.c index f769b14d..face40b3 100644 --- a/datapath/flow.c +++ b/datapath/flow.c @@ -34,59 +34,53 @@ struct kmem_cache *flow_cache; static unsigned int hash_seed; -struct arp_eth_header +static inline bool arphdr_ok(struct sk_buff *skb) { - __be16 ar_hrd; /* format of hardware address */ - __be16 ar_pro; /* format of protocol address */ - unsigned char ar_hln; /* length of hardware address */ - unsigned char ar_pln; /* length of protocol address */ - __be16 ar_op; /* ARP opcode (command) */ - - /* Ethernet+IPv4 specific members. */ - unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */ - unsigned char ar_sip[4]; /* sender IP address */ - unsigned char ar_tha[ETH_ALEN]; /* target hardware address */ - unsigned char ar_tip[4]; /* target IP address */ -} __attribute__((packed)); - -static inline int arphdr_ok(struct sk_buff *skb) -{ - int nh_ofs = skb_network_offset(skb); - return pskb_may_pull(skb, nh_ofs + sizeof(struct arp_eth_header)); + return skb->len >= skb_network_offset(skb) + sizeof(struct arp_eth_header); } -static inline int iphdr_ok(struct sk_buff *skb) +static inline int check_iphdr(struct sk_buff *skb) { - int nh_ofs = skb_network_offset(skb); - if (skb->len >= nh_ofs + sizeof(struct iphdr)) { - int ip_len = ip_hdrlen(skb); - return (ip_len >= sizeof(struct iphdr) - && pskb_may_pull(skb, nh_ofs + ip_len)); - } + unsigned int nh_ofs = skb_network_offset(skb); + unsigned int ip_len; + + if (skb->len < nh_ofs + sizeof(struct iphdr)) + return -EINVAL; + + ip_len = ip_hdrlen(skb); + if (ip_len < sizeof(struct iphdr) || skb->len < nh_ofs + ip_len) + return -EINVAL; + + /* + * Pull enough header bytes to account for the IP header plus the + * longest transport header that we parse, currently 20 bytes for TCP. + */ + if (!pskb_may_pull(skb, min(nh_ofs + ip_len + 20, skb->len))) + return -ENOMEM; + + skb_set_transport_header(skb, nh_ofs + ip_len); return 0; } -static inline int tcphdr_ok(struct sk_buff *skb) +static inline bool tcphdr_ok(struct sk_buff *skb) { int th_ofs = skb_transport_offset(skb); - if (pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))) { + if (skb->len >= th_ofs + sizeof(struct tcphdr)) { int tcp_len = tcp_hdrlen(skb); return (tcp_len >= sizeof(struct tcphdr) && skb->len >= th_ofs + tcp_len); } - return 0; + return false; } -static inline int udphdr_ok(struct sk_buff *skb) +static inline bool udphdr_ok(struct sk_buff *skb) { - int th_ofs = skb_transport_offset(skb); - return pskb_may_pull(skb, th_ofs + sizeof(struct udphdr)); + return skb->len >= skb_transport_offset(skb) + sizeof(struct udphdr); } -static inline int icmphdr_ok(struct sk_buff *skb) +static inline bool icmphdr_ok(struct sk_buff *skb) { - int th_ofs = skb_transport_offset(skb); - return pskb_may_pull(skb, th_ofs + sizeof(struct icmphdr)); + return skb->len >= skb_transport_offset(skb) + sizeof(struct icmphdr); } #define TCP_FLAGS_OFFSET 13 @@ -114,7 +108,10 @@ struct sw_flow_actions *flow_actions_alloc(size_t n_actions) { struct sw_flow_actions *sfa; - if (n_actions > (PAGE_SIZE - sizeof *sfa) / sizeof(union odp_action)) + /* At least DP_MAX_PORTS actions are required to be able to flood a + * packet to every port. Factor of 2 allows for setting VLAN tags, + * etc. */ + if (n_actions > 2 * DP_MAX_PORTS) return ERR_PTR(-EINVAL); sfa = kmalloc(sizeof *sfa + n_actions * sizeof(union odp_action), @@ -126,27 +123,36 @@ struct sw_flow_actions *flow_actions_alloc(size_t n_actions) return sfa; } - -/* Frees 'flow' immediately. */ -static void flow_free(struct sw_flow *flow) +struct sw_flow *flow_alloc(void) { - if (unlikely(!flow)) - return; - kfree(flow->sf_acts); - kmem_cache_free(flow_cache, flow); + struct sw_flow *flow; + + flow = kmem_cache_alloc(flow_cache, GFP_KERNEL); + if (!flow) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&flow->lock); + atomic_set(&flow->refcnt, 1); + flow->dead = false; + + return flow; } void flow_free_tbl(struct tbl_node *node) { struct sw_flow *flow = flow_cast(node); - flow_free(flow); + + flow->dead = true; + flow_put(flow); } /* RCU callback used by flow_deferred_free. */ static void rcu_free_flow_callback(struct rcu_head *rcu) { struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu); - flow_free(flow); + + flow->dead = true; + flow_put(flow); } /* Schedules 'flow' to be freed after the next RCU grace period. @@ -156,10 +162,26 @@ void flow_deferred_free(struct sw_flow *flow) call_rcu(&flow->rcu, rcu_free_flow_callback); } +void flow_hold(struct sw_flow *flow) +{ + atomic_inc(&flow->refcnt); +} + +void flow_put(struct sw_flow *flow) +{ + if (unlikely(!flow)) + return; + + if (atomic_dec_and_test(&flow->refcnt)) { + kfree(flow->sf_acts); + kmem_cache_free(flow_cache, flow); + } +} + /* RCU callback used by flow_deferred_free_acts. */ static void rcu_free_acts_callback(struct rcu_head *rcu) { - struct sw_flow_actions *sf_acts = container_of(rcu, + struct sw_flow_actions *sf_acts = container_of(rcu, struct sw_flow_actions, rcu); kfree(sf_acts); } @@ -183,8 +205,7 @@ static void parse_vlan(struct sk_buff *skb, struct odp_flow_key *key) return; qp = (struct qtag_prefix *) skb->data; - key->dl_vlan = qp->tci & htons(VLAN_VID_MASK); - key->dl_vlan_pcp = (ntohs(qp->tci) & VLAN_PCP_MASK) >> VLAN_PCP_SHIFT; + key->dl_tci = qp->tci | htons(ODP_TCI_PRESENT); __skb_pull(skb, sizeof(struct qtag_prefix)); } @@ -219,23 +240,63 @@ static __be16 parse_ethertype(struct sk_buff *skb) return llc->ethertype; } -/* Parses the Ethernet frame in 'skb', which was received on 'in_port', - * and initializes 'key' to match. Returns 1 if 'skb' contains an IP - * fragment, 0 otherwise. */ -int flow_extract(struct sk_buff *skb, u16 in_port, struct odp_flow_key *key) +/** + * flow_extract - extracts a flow key from an Ethernet frame. + * @skb: sk_buff that contains the frame, with skb->data pointing to the + * Ethernet header + * @in_port: port number on which @skb was received. + * @key: output flow key + * @is_frag: set to 1 if @skb contains an IPv4 fragment, or to 0 if @skb does + * not contain an IPv4 packet or if it is not a fragment. + * + * The caller must ensure that skb->len >= ETH_HLEN. + * + * Returns 0 if successful, otherwise a negative errno value. + * + * Initializes @skb header pointers as follows: + * + * - skb->mac_header: the Ethernet header. + * + * - skb->network_header: just past the Ethernet header, or just past the + * VLAN header, to the first byte of the Ethernet payload. + * + * - skb->transport_header: If key->dl_type is ETH_P_IP on output, then just + * past the IPv4 header, if one is present and of a correct length, + * otherwise the same as skb->network_header. For other key->dl_type + * values it is left untouched. + * + * Sets OVS_CB(skb)->is_frag to %true if @skb is an IPv4 fragment, otherwise to + * %false. + */ +int flow_extract(struct sk_buff *skb, u16 in_port, struct odp_flow_key *key, + bool *is_frag) { struct ethhdr *eth; - int retval = 0; memset(key, 0, sizeof *key); key->tun_id = OVS_CB(skb)->tun_id; key->in_port = in_port; - key->dl_vlan = htons(ODP_VLAN_NONE); - - if (skb->len < sizeof *eth) - return 0; - if (!pskb_may_pull(skb, skb->len >= 64 ? 64 : skb->len)) - return 0; + *is_frag = false; + + /* + * We would really like to pull as many bytes as we could possibly + * want to parse into the linear data area. Currently that is: + * + * 14 Ethernet header + * 4 VLAN header + * 60 max IP header with options + * 20 max TCP/UDP/ICMP header (don't care about options) + * -- + * 98 + * + * But Xen only allocates 64 or 72 bytes for the linear data area in + * netback, which means that we would reallocate and copy the skb's + * linear data on every packet if we did that. So instead just pull 64 + * bytes, which is always sufficient without IP options, and then check + * whether we need to pull more later when we look at the IP header. + */ + if (!pskb_may_pull(skb, min(skb->len, 64u))) + return -ENOMEM; skb_reset_mac_header(skb); @@ -253,14 +314,24 @@ int flow_extract(struct sk_buff *skb, u16 in_port, struct odp_flow_key *key) __skb_push(skb, skb->data - (unsigned char *)eth); /* Network layer. */ - if (key->dl_type == htons(ETH_P_IP) && iphdr_ok(skb)) { - struct iphdr *nh = ip_hdr(skb); - int th_ofs = skb_network_offset(skb) + nh->ihl * 4; + if (key->dl_type == htons(ETH_P_IP)) { + struct iphdr *nh; + int error; + + error = check_iphdr(skb); + if (unlikely(error)) { + if (error == -EINVAL) { + skb->transport_header = skb->network_header; + return 0; + } + return error; + } + + nh = ip_hdr(skb); key->nw_src = nh->saddr; key->nw_dst = nh->daddr; key->nw_tos = nh->tos & ~INET_ECN_MASK; key->nw_proto = nh->protocol; - skb_set_transport_header(skb, th_ofs); /* Transport layer. */ if (!(nh->frag_off & htons(IP_MF | IP_OFFSET))) { @@ -269,22 +340,12 @@ int flow_extract(struct sk_buff *skb, u16 in_port, struct odp_flow_key *key) struct tcphdr *tcp = tcp_hdr(skb); key->tp_src = tcp->source; key->tp_dst = tcp->dest; - } else { - /* Avoid tricking other code into - * thinking that this packet has an L4 - * header. */ - key->nw_proto = 0; } } else if (key->nw_proto == IPPROTO_UDP) { if (udphdr_ok(skb)) { struct udphdr *udp = udp_hdr(skb); key->tp_src = udp->source; key->tp_dst = udp->dest; - } else { - /* Avoid tricking other code into - * thinking that this packet has an L4 - * header. */ - key->nw_proto = 0; } } else if (key->nw_proto == IPPROTO_ICMP) { if (icmphdr_ok(skb)) { @@ -294,16 +355,11 @@ int flow_extract(struct sk_buff *skb, u16 in_port, struct odp_flow_key *key) * in 16-bit network byte order. */ key->tp_src = htons(icmp->type); key->tp_dst = htons(icmp->code); - } else { - /* Avoid tricking other code into - * thinking that this packet has an L4 - * header. */ - key->nw_proto = 0; } } - } else { - retval = 1; - } + } else + *is_frag = true; + } else if (key->dl_type == htons(ETH_P_ARP) && arphdr_ok(skb)) { struct arp_eth_header *arp; @@ -315,20 +371,17 @@ int flow_extract(struct sk_buff *skb, u16 in_port, struct odp_flow_key *key) && arp->ar_pln == 4) { /* We only match on the lower 8 bits of the opcode. */ - if (ntohs(arp->ar_op) <= 0xff) { + if (ntohs(arp->ar_op) <= 0xff) key->nw_proto = ntohs(arp->ar_op); - } - if (key->nw_proto == ARPOP_REQUEST + if (key->nw_proto == ARPOP_REQUEST || key->nw_proto == ARPOP_REPLY) { memcpy(&key->nw_src, arp->ar_sip, sizeof(key->nw_src)); memcpy(&key->nw_dst, arp->ar_tip, sizeof(key->nw_dst)); } } - } else { - skb_reset_transport_header(skb); } - return retval; + return 0; } u32 flow_hash(const struct odp_flow_key *key)