datapath: Simplify ODPAT_SET_DL_TCI action.
[sliver-openvswitch.git] / datapath / actions.c
index a6771b6..5904c83 100644 (file)
@@ -14,6 +14,7 @@
 #include <linux/tcp.h>
 #include <linux/udp.h>
 #include <linux/in6.h>
+#include <linux/if_arp.h>
 #include <linux/if_vlan.h>
 #include <net/inet_ecn.h>
 #include <net/ip.h>
 #include "openvswitch/datapath-protocol.h"
 #include "vport.h"
 
-static struct sk_buff *make_writable(struct sk_buff *skb, unsigned min_headroom, gfp_t gfp)
+static struct sk_buff *make_writable(struct sk_buff *skb, unsigned min_headroom)
 {
        if (skb_cloned(skb)) {
                struct sk_buff *nskb;
                unsigned headroom = max(min_headroom, skb_headroom(skb));
 
-               nskb = skb_copy_expand(skb, headroom, skb_tailroom(skb), gfp);
+               nskb = skb_copy_expand(skb, headroom, skb_tailroom(skb), GFP_ATOMIC);
                if (nskb) {
                        set_skb_csum_bits(skb, nskb);
                        kfree_skb(skb);
@@ -52,7 +53,7 @@ static struct sk_buff *vlan_pull_tag(struct sk_buff *skb)
        struct ethhdr *eh;
 
        /* Verify we were given a vlan packet */
-       if (vh->h_vlan_proto != htons(ETH_P_8021Q))
+       if (vh->h_vlan_proto != htons(ETH_P_8021Q) || skb->len < VLAN_ETH_HLEN)
                return skb;
 
        if (OVS_CB(skb)->ip_summed == OVS_CSUM_COMPLETE)
@@ -71,29 +72,26 @@ static struct sk_buff *vlan_pull_tag(struct sk_buff *skb)
 
 static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
                                       const struct odp_flow_key *key,
-                                      const union odp_action *a, int n_actions,
-                                      gfp_t gfp)
+                                      const union odp_action *a, int n_actions)
 {
-       u16 tci, mask;
+       __be16 tci = a->dl_tci.tci;
 
-       if (a->type == ODPAT_SET_VLAN_VID) {
-               tci = ntohs(a->vlan_vid.vlan_vid);
-               mask = VLAN_VID_MASK;
-       } else {
-               tci = a->vlan_pcp.vlan_pcp << VLAN_PCP_SHIFT;
-               mask = VLAN_PCP_MASK;
-       }
-
-       skb = make_writable(skb, VLAN_HLEN, gfp);
+       skb = make_writable(skb, VLAN_HLEN);
        if (!skb)
                return ERR_PTR(-ENOMEM);
 
        if (skb->protocol == htons(ETH_P_8021Q)) {
                /* Modify vlan id, but maintain other TCI values */
-               struct vlan_ethhdr *vh = vlan_eth_hdr(skb);
-               __be16 old_tci = vh->h_vlan_TCI;
+               struct vlan_ethhdr *vh;
+               __be16 old_tci;
 
-               vh->h_vlan_TCI = htons((ntohs(vh->h_vlan_TCI) & ~mask) | tci);
+               if (skb->len < VLAN_ETH_HLEN)
+                       return skb;
+
+               vh = vlan_eth_hdr(skb);
+               old_tci = vh->h_vlan_TCI;
+
+               vh->h_vlan_TCI = tci;
 
                if (OVS_CB(skb)->ip_summed == OVS_CSUM_COMPLETE) {
                        __be16 diff[] = { ~old_tci, vh->h_vlan_TCI };
@@ -115,7 +113,7 @@ static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
                if (unlikely(err)) {
                        kfree_skb(skb);
                        return ERR_PTR(err);
-               }       
+               }
 
                /* GSO is not implemented for packets with an 802.1Q header, so
                 * we have to do segmentation before we add that header.
@@ -149,13 +147,12 @@ static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
                                /* GSO can change the checksum type so update.*/
                                compute_ip_summed(segs, true);
 
-                               segs = __vlan_put_tag(segs, tci);
+                               segs = __vlan_put_tag(segs, ntohs(tci));
                                err = -ENOMEM;
                                if (segs) {
                                        err = execute_actions(dp, segs,
                                                              key, a + 1,
-                                                             n_actions - 1,
-                                                             gfp);
+                                                             n_actions - 1);
                                }
 
                                if (unlikely(err)) {
@@ -179,7 +176,7 @@ static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
                 * e.g. vconfig(8)), so call the software-only version
                 * __vlan_put_tag() directly instead.
                 */
-               skb = __vlan_put_tag(skb, tci);
+               skb = __vlan_put_tag(skb, ntohs(tci));
                if (!skb)
                        return ERR_PTR(-ENOMEM);
 
@@ -193,20 +190,18 @@ static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
        return skb;
 }
 
-static struct sk_buff *strip_vlan(struct sk_buff *skb, gfp_t gfp)
+static struct sk_buff *strip_vlan(struct sk_buff *skb)
 {
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (skb)
                vlan_pull_tag(skb);
-
        return skb;
 }
 
 static struct sk_buff *set_dl_addr(struct sk_buff *skb,
-                                  const struct odp_action_dl_addr *a,
-                                  gfp_t gfp)
+                                  const struct odp_action_dl_addr *a)
 {
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (skb) {
                struct ethhdr *eh = eth_hdr(skb);
                if (a->type == ODPAT_SET_DL_SRC)
@@ -237,43 +232,61 @@ static void update_csum(__sum16 *sum, struct sk_buff *skb,
                                csum_unfold(*sum)));
 }
 
+static bool is_ip(struct sk_buff *skb, const struct odp_flow_key *key)
+{
+       return (key->dl_type == htons(ETH_P_IP) &&
+               skb->transport_header > skb->network_header);
+}
+
+static __sum16 *get_l4_checksum(struct sk_buff *skb, const struct odp_flow_key *key)
+{
+       int transport_len = skb->len - skb_transport_offset(skb);
+       if (key->nw_proto == IPPROTO_TCP) {
+               if (likely(transport_len >= sizeof(struct tcphdr)))
+                       return &tcp_hdr(skb)->check;
+       } else if (key->nw_proto == IPPROTO_UDP) {
+               if (likely(transport_len >= sizeof(struct udphdr)))
+                       return &udp_hdr(skb)->check;
+       }
+       return NULL;
+}
+
 static struct sk_buff *set_nw_addr(struct sk_buff *skb,
                                   const struct odp_flow_key *key,
-                                  const struct odp_action_nw_addr *a,
-                                  gfp_t gfp)
+                                  const struct odp_action_nw_addr *a)
 {
-       if (key->dl_type != htons(ETH_P_IP))
+       struct iphdr *nh;
+       __sum16 *check;
+       __be32 *nwaddr;
+
+       if (unlikely(!is_ip(skb, key)))
                return skb;
 
-       skb = make_writable(skb, 0, gfp);
-       if (skb) {
-               struct iphdr *nh = ip_hdr(skb);
-               u32 *f = a->type == ODPAT_SET_NW_SRC ? &nh->saddr : &nh->daddr;
-               u32 old = *f;
-               u32 new = a->nw_addr;
-
-               if (key->nw_proto == IPPROTO_TCP) {
-                       struct tcphdr *th = tcp_hdr(skb);
-                       update_csum(&th->check, skb, old, new, 1);
-               } else if (key->nw_proto == IPPROTO_UDP) {
-                       struct udphdr *th = udp_hdr(skb);
-                       update_csum(&th->check, skb, old, new, 1);
-               }
-               update_csum(&nh->check, skb, old, new, 0);
-               *f = new;
-       }
+       skb = make_writable(skb, 0);
+       if (unlikely(!skb))
+               return NULL;
+
+       nh = ip_hdr(skb);
+       nwaddr = a->type == ODPAT_SET_NW_SRC ? &nh->saddr : &nh->daddr;
+
+       check = get_l4_checksum(skb, key);
+       if (likely(check))
+               update_csum(check, skb, *nwaddr, a->nw_addr, 1);
+       update_csum(&nh->check, skb, *nwaddr, a->nw_addr, 0);
+
+       *nwaddr = a->nw_addr;
+
        return skb;
 }
 
 static struct sk_buff *set_nw_tos(struct sk_buff *skb,
                                   const struct odp_flow_key *key,
-                                  const struct odp_action_nw_tos *a,
-                                  gfp_t gfp)
+                                  const struct odp_action_nw_tos *a)
 {
-       if (key->dl_type != htons(ETH_P_IP))
+       if (unlikely(!is_ip(skb, key)))
                return skb;
 
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (skb) {
                struct iphdr *nh = ip_hdr(skb);
                u8 *f = &nh->tos;
@@ -282,8 +295,8 @@ static struct sk_buff *set_nw_tos(struct sk_buff *skb,
 
                /* Set the DSCP bits and preserve the ECN bits. */
                new = a->nw_tos | (nh->tos & INET_ECN_MASK);
-               update_csum(&nh->check, skb, htons((uint16_t)old),
-                               htons((uint16_t)new), 0);
+               update_csum(&nh->check, skb, htons((u16)old),
+                           htons((u16)new), 0);
                *f = new;
        }
        return skb;
@@ -291,33 +304,68 @@ static struct sk_buff *set_nw_tos(struct sk_buff *skb,
 
 static struct sk_buff *set_tp_port(struct sk_buff *skb,
                                   const struct odp_flow_key *key,
-                                  const struct odp_action_tp_port *a, gfp_t gfp)
+                                  const struct odp_action_tp_port *a)
 {
-       int check_ofs;
+       struct udphdr *th;
+       __sum16 *check;
+       __be16 *port;
 
-       if (key->dl_type != htons(ETH_P_IP))
+       if (unlikely(!is_ip(skb, key)))
                return skb;
 
-       if (key->nw_proto == IPPROTO_TCP)
-               check_ofs = offsetof(struct tcphdr, check);
-       else if (key->nw_proto == IPPROTO_UDP)
-               check_ofs = offsetof(struct udphdr, check);
-       else
+       skb = make_writable(skb, 0);
+       if (unlikely(!skb))
+               return NULL;
+
+       /* Must follow make_writable() since that can move the skb data. */
+       check = get_l4_checksum(skb, key);
+       if (unlikely(!check))
                return skb;
 
-       skb = make_writable(skb, 0, gfp);
-       if (skb) {
-               struct udphdr *th = udp_hdr(skb);
-               u16 *f = a->type == ODPAT_SET_TP_SRC ? &th->source : &th->dest;
-               u16 old = *f;
-               u16 new = a->tp_port;
-               update_csum((u16*)(skb_transport_header(skb) + check_ofs), 
-                               skb, old, new, 0);
-               *f = new;
-       }
+       /*
+        * Update port and checksum.
+        *
+        * This is OK because source and destination port numbers are at the
+        * same offsets in both UDP and TCP headers, and get_l4_checksum() only
+        * supports those protocols.
+        */
+       th = udp_hdr(skb);
+       port = a->type == ODPAT_SET_TP_SRC ? &th->source : &th->dest;
+       update_csum(check, skb, *port, a->tp_port, 0);
+       *port = a->tp_port;
+
        return skb;
 }
 
+/**
+ * is_spoofed_arp - check for invalid ARP packet
+ *
+ * @skb: skbuff containing an Ethernet packet, with network header pointing
+ * just past the Ethernet and optional 802.1Q header.
+ * @key: flow key extracted from @skb by flow_extract()
+ *
+ * Returns true if @skb is an invalid Ethernet+IPv4 ARP packet: one with screwy
+ * or truncated header fields or one whose inner and outer Ethernet address
+ * differ.
+ */
+static bool is_spoofed_arp(struct sk_buff *skb, const struct odp_flow_key *key)
+{
+       struct arp_eth_header *arp;
+
+       if (key->dl_type != htons(ETH_P_ARP))
+               return false;
+
+       if (skb_network_offset(skb) + sizeof(struct arp_eth_header) > skb->len)
+               return true;
+
+       arp = (struct arp_eth_header *)skb_network_header(skb);
+       return (arp->ar_hrd != htons(ARPHRD_ETHER) ||
+               arp->ar_pro != htons(ETH_P_IP) ||
+               arp->ar_hln != ETH_ALEN ||
+               arp->ar_pln != 4 ||
+               compare_ether_addr(arp->ar_sha, eth_hdr(skb)->h_source));
+}
+
 static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
 {
        struct dp_port *p;
@@ -336,36 +384,9 @@ error:
        kfree_skb(skb);
 }
 
-/* Never consumes 'skb'.  Returns a port that 'skb' should be sent to, -1 if
- * none.  */
-static int output_group(struct datapath *dp, __u16 group,
-                       struct sk_buff *skb, gfp_t gfp)
+static int output_control(struct datapath *dp, struct sk_buff *skb, u32 arg)
 {
-       struct dp_port_group *g = rcu_dereference(dp->groups[group]);
-       int prev_port = -1;
-       int i;
-
-       if (!g)
-               return -1;
-       for (i = 0; i < g->n_ports; i++) {
-               struct dp_port *p = rcu_dereference(dp->ports[g->ports[i]]);
-               if (!p || OVS_CB(skb)->dp_port == p)
-                       continue;
-               if (prev_port != -1) {
-                       struct sk_buff *clone = skb_clone(skb, gfp);
-                       if (!clone)
-                               return -1;
-                       do_output(dp, clone, prev_port);
-               }
-               prev_port = p->port_no;
-       }
-       return prev_port;
-}
-
-static int output_control(struct datapath *dp, struct sk_buff *skb, u32 arg,
-                         gfp_t gfp)
-{
-       skb = skb_clone(skb, gfp);
+       skb = skb_clone(skb, GFP_ATOMIC);
        if (!skb)
                return -ENOMEM;
        return dp_output_control(dp, skb, _ODPL_ACTION_NR, arg);
@@ -375,14 +396,14 @@ static int output_control(struct datapath *dp, struct sk_buff *skb, u32 arg,
  * information about what happened to it. */
 static void sflow_sample(struct datapath *dp, struct sk_buff *skb,
                         const union odp_action *a, int n_actions,
-                        gfp_t gfp, struct dp_port *dp_port)
+                        struct dp_port *dp_port)
 {
        struct odp_sflow_sample_header *hdr;
        unsigned int actlen = n_actions * sizeof(union odp_action);
        unsigned int hdrlen = sizeof(struct odp_sflow_sample_header);
        struct sk_buff *nskb;
 
-       nskb = skb_copy_expand(skb, actlen + hdrlen, 0, gfp);
+       nskb = skb_copy_expand(skb, actlen + hdrlen, 0, GFP_ATOMIC);
        if (!nskb)
                return;
 
@@ -396,8 +417,7 @@ static void sflow_sample(struct datapath *dp, struct sk_buff *skb,
 /* Execute a list of actions against 'skb'. */
 int execute_actions(struct datapath *dp, struct sk_buff *skb,
                    const struct odp_flow_key *key,
-                   const union odp_action *a, int n_actions,
-                   gfp_t gfp)
+                   const union odp_action *a, int n_actions)
 {
        /* Every output action needs a separate clone of 'skb', but the common
         * case is just a single output action, so that doing a clone and
@@ -413,7 +433,7 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                        atomic_inc(&p->sflow_pool);
                        if (dp->sflow_probability == UINT_MAX ||
                            net_random() < dp->sflow_probability)
-                               sflow_sample(dp, skb, a, n_actions, gfp, p);
+                               sflow_sample(dp, skb, a, n_actions, p);
                }
        }
 
@@ -421,7 +441,7 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
 
        for (; n_actions > 0; a++, n_actions--) {
                if (prev_port != -1) {
-                       do_output(dp, skb_clone(skb, gfp), prev_port);
+                       do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
                        prev_port = -1;
                }
 
@@ -430,13 +450,8 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                        prev_port = a->output.port;
                        break;
 
-               case ODPAT_OUTPUT_GROUP:
-                       prev_port = output_group(dp, a->output_group.group,
-                                                skb, gfp);
-                       break;
-
                case ODPAT_CONTROLLER:
-                       err = output_control(dp, skb, a->controller.arg, gfp);
+                       err = output_control(dp, skb, a->controller.arg);
                        if (err) {
                                kfree_skb(skb);
                                return err;
@@ -447,34 +462,33 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                        OVS_CB(skb)->tun_id = a->tunnel.tun_id;
                        break;
 
-               case ODPAT_SET_VLAN_VID:
-               case ODPAT_SET_VLAN_PCP:
-                       skb = modify_vlan_tci(dp, skb, key, a, n_actions, gfp);
+               case ODPAT_SET_DL_TCI:
+                       skb = modify_vlan_tci(dp, skb, key, a, n_actions);
                        if (IS_ERR(skb))
                                return PTR_ERR(skb);
                        break;
 
                case ODPAT_STRIP_VLAN:
-                       skb = strip_vlan(skb, gfp);
+                       skb = strip_vlan(skb);
                        break;
 
                case ODPAT_SET_DL_SRC:
                case ODPAT_SET_DL_DST:
-                       skb = set_dl_addr(skb, &a->dl_addr, gfp);
+                       skb = set_dl_addr(skb, &a->dl_addr);
                        break;
 
                case ODPAT_SET_NW_SRC:
                case ODPAT_SET_NW_DST:
-                       skb = set_nw_addr(skb, key, &a->nw_addr, gfp);
+                       skb = set_nw_addr(skb, key, &a->nw_addr);
                        break;
 
                case ODPAT_SET_NW_TOS:
-                       skb = set_nw_tos(skb, key, &a->nw_tos, gfp);
+                       skb = set_nw_tos(skb, key, &a->nw_tos);
                        break;
 
                case ODPAT_SET_TP_SRC:
                case ODPAT_SET_TP_DST:
-                       skb = set_tp_port(skb, key, &a->tp_port, gfp);
+                       skb = set_tp_port(skb, key, &a->tp_port);
                        break;
 
                case ODPAT_SET_PRIORITY:
@@ -484,10 +498,16 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                case ODPAT_POP_PRIORITY:
                        skb->priority = priority;
                        break;
+
+               case ODPAT_DROP_SPOOFED_ARP:
+                       if (unlikely(is_spoofed_arp(skb, key)))
+                               goto exit;
+                       break;
                }
                if (!skb)
                        return -ENOMEM;
        }
+exit:
        if (prev_port != -1)
                do_output(dp, skb, prev_port);
        else