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udp: Always hash socket facing flowsides
For UDP packets from the tap interface (like TCP) we use a hash table to look up which flow they belong to. Unlike TCP, we sometimes also create a hash table entry for the socket side of UDP flows. We need that when we receive a UDP packet from a "listening" socket which isn't specific to a single flow. At present we only do this for the initiating side of flows, which re-use the listening socket. For the target side we use a connected "reply" socket specific to the single flow. We have in mind changes that maye introduce some edge cases were we could receive UDP packets on a non flow specific socket more often. To allow for those changes - and slightly simplifying things in the meantime - always put both sides of a UDP flow - tap or socket - in the hash table. It's not that costly, and means we always have the option of falling back to a hash lookup. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
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parent
f67c488b81
commit
37d78c9ef3
1 changed files with 20 additions and 21 deletions
41
udp_flow.c
41
udp_flow.c
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@ -41,25 +41,23 @@ struct udp_flow *udp_at_sidx(flow_sidx_t sidx)
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*/
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*/
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void udp_flow_close(const struct ctx *c, struct udp_flow *uflow)
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void udp_flow_close(const struct ctx *c, struct udp_flow *uflow)
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{
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{
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unsigned sidei;
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if (uflow->closed)
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if (uflow->closed)
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return; /* Nothing to do */
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return; /* Nothing to do */
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if (uflow->s[INISIDE] >= 0) {
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flow_foreach_sidei(sidei) {
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/* The listening socket needs to stay in epoll */
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flow_hash_remove(c, FLOW_SIDX(uflow, sidei));
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close(uflow->s[INISIDE]);
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if (uflow->s[sidei] >= 0) {
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uflow->s[INISIDE] = -1;
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/* The listening socket needs to stay in epoll, but the
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* flow specific one needs to be removed */
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if (sidei == TGTSIDE)
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epoll_del(c, uflow->s[sidei]);
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close(uflow->s[sidei]);
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uflow->s[sidei] = -1;
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}
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}
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}
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if (uflow->s[TGTSIDE] >= 0) {
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/* But the flow specific one needs to be removed */
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epoll_del(c, uflow->s[TGTSIDE]);
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close(uflow->s[TGTSIDE]);
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uflow->s[TGTSIDE] = -1;
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}
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flow_hash_remove(c, FLOW_SIDX(uflow, INISIDE));
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if (!pif_is_socket(uflow->f.pif[TGTSIDE]))
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flow_hash_remove(c, FLOW_SIDX(uflow, TGTSIDE));
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uflow->closed = true;
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uflow->closed = true;
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}
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}
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@ -77,6 +75,7 @@ static flow_sidx_t udp_flow_new(const struct ctx *c, union flow *flow,
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{
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{
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struct udp_flow *uflow = NULL;
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struct udp_flow *uflow = NULL;
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const struct flowside *tgt;
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const struct flowside *tgt;
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unsigned sidei;
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uint8_t tgtpif;
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uint8_t tgtpif;
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if (!(tgt = flow_target(c, flow, IPPROTO_UDP)))
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if (!(tgt = flow_target(c, flow, IPPROTO_UDP)))
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@ -143,14 +142,14 @@ static flow_sidx_t udp_flow_new(const struct ctx *c, union flow *flow,
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}
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}
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}
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}
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flow_hash_insert(c, FLOW_SIDX(uflow, INISIDE));
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/* Tap sides always need to be looked up by hash. Socket sides don't
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* always, but sometimes do (receiving packets on a socket not specific
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/* If the target side is a socket, it will be a reply socket that knows
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* to one flow). Unconditionally hash both sides so all our bases are
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* its own flowside. But if it's tap, then we need to look it up by
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* covered
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* hash.
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*/
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*/
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if (!pif_is_socket(tgtpif))
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flow_foreach_sidei(sidei)
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flow_hash_insert(c, FLOW_SIDX(uflow, TGTSIDE));
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flow_hash_insert(c, FLOW_SIDX(uflow, sidei));
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FLOW_ACTIVATE(uflow);
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FLOW_ACTIVATE(uflow);
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return FLOW_SIDX(uflow, TGTSIDE);
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return FLOW_SIDX(uflow, TGTSIDE);
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