+mod_flow(struct sw_chain *chain, const struct ofp_flow_mod *ofm)
+{
+ int error = -ENOMEM;
+ int i;
+ int n_actions;
+ struct sw_flow_key key;
+ uint16_t priority;
+ int strict;
+
+ /* To prevent loops, make sure there's no action to send to the
+ * OFP_TABLE virtual port.
+ */
+ n_actions = (ntohs(ofm->header.length) - sizeof *ofm)
+ / sizeof *ofm->actions;
+ for (i=0; i<n_actions; i++) {
+ const struct ofp_action *a = &ofm->actions[i];
+
+ if (a->type == htons(OFPAT_OUTPUT)
+ && (a->arg.output.port == htons(OFPP_TABLE)
+ || a->arg.output.port == htons(OFPP_NONE)
+ || a->arg.output.port == ofm->match.in_port)) {
+ /* xxx Send fancy new error message? */
+ goto error;
+ }
+ }
+
+ flow_extract_match(&key, &ofm->match);
+ priority = key.wildcards ? ntohs(ofm->priority) : -1;
+ strict = (ofm->command == htons(OFPFC_MODIFY_STRICT)) ? 1 : 0;
+ chain_modify(chain, &key, priority, strict, ofm->actions, n_actions);
+
+ if (ntohl(ofm->buffer_id) != (uint32_t) -1) {
+ struct sk_buff *skb = retrieve_skb(ntohl(ofm->buffer_id));
+ if (skb) {
+ struct sw_flow_key skb_key;
+ flow_extract(skb, ntohs(ofm->match.in_port), &skb_key);
+ execute_actions(chain->dp, skb, &skb_key,
+ ofm->actions, n_actions, 0);
+ }
+ else
+ error = -ESRCH;
+ }
+ return error;
+
+error:
+ if (ntohl(ofm->buffer_id) != (uint32_t) -1)
+ discard_skb(ntohl(ofm->buffer_id));
+ return error;
+}
+
+static int
+recv_flow(struct sw_chain *chain, const struct sender *sender, const void *msg)