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udp: Add helper function for creating connected UDP socket
Currently udp_flow_new() open codes creating and connecting a socket to use for reply messages. We have in mind some more places to use this logic, plus it just makes for a rather large function. Split this handling out into a new udp_flow_sock() function. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
parent
37d78c9ef3
commit
77883fbdd1
1 changed files with 58 additions and 46 deletions
104
udp_flow.c
104
udp_flow.c
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@ -61,6 +61,61 @@ void udp_flow_close(const struct ctx *c, struct udp_flow *uflow)
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uflow->closed = true;
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}
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/**
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* udp_flow_sock() - Create, bind and connect a flow specific UDP socket
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* @c: Execution context
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* @uflow: UDP flow to open socket for
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* @sidei: Side of @uflow to open socket for
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*
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* Return: fd of new socket on success, -ve error code on failure
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*/
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static int udp_flow_sock(const struct ctx *c,
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const struct udp_flow *uflow, unsigned sidei)
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{
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const struct flowside *side = &uflow->f.side[sidei];
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struct mmsghdr discard[UIO_MAXIOV] = { 0 };
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uint8_t pif = uflow->f.pif[sidei];
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union {
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flow_sidx_t sidx;
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uint32_t data;
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} fref = { .sidx = FLOW_SIDX(uflow, sidei) };
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int rc, s;
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s = flowside_sock_l4(c, EPOLL_TYPE_UDP_REPLY, pif, side, fref.data);
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if (s < 0) {
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flow_dbg_perror(uflow, "Couldn't open flow specific socket");
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return s;
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}
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if (flowside_connect(c, s, pif, side) < 0) {
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rc = -errno;
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flow_dbg_perror(uflow, "Couldn't connect flow socket");
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return rc;
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}
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/* It's possible, if unlikely, that we could receive some unrelated
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* packets in between the bind() and connect() of this socket. For now
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* we just discard these.
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*
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* FIXME: Redirect these to an appropriate handler
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*/
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rc = recvmmsg(s, discard, ARRAY_SIZE(discard), MSG_DONTWAIT, NULL);
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if (rc >= ARRAY_SIZE(discard)) {
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flow_dbg(uflow, "Too many (%d) spurious reply datagrams", rc);
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return -E2BIG;
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}
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if (rc > 0) {
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flow_trace(uflow, "Discarded %d spurious reply datagrams", rc);
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} else if (errno != EAGAIN) {
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rc = -errno;
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flow_perror(uflow, "Unexpected error discarding datagrams");
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return rc;
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}
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return s;
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}
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/**
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* udp_flow_new() - Common setup for a new UDP flow
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* @c: Execution context
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@ -74,13 +129,10 @@ static flow_sidx_t udp_flow_new(const struct ctx *c, union flow *flow,
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int s_ini, const struct timespec *now)
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{
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struct udp_flow *uflow = NULL;
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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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if (!(tgt = flow_target(c, flow, IPPROTO_UDP)))
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if (!flow_target(c, flow, IPPROTO_UDP))
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goto cancel;
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tgtpif = flow->f.pif[TGTSIDE];
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uflow = FLOW_SET_TYPE(flow, FLOW_UDP, udp);
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uflow->ts = now->tv_sec;
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@ -98,49 +150,9 @@ 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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if (pif_is_socket(tgtpif)) {
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struct mmsghdr discard[UIO_MAXIOV] = { 0 };
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union {
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flow_sidx_t sidx;
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uint32_t data;
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} fref = {
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.sidx = FLOW_SIDX(flow, TGTSIDE),
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};
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int rc;
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uflow->s[TGTSIDE] = flowside_sock_l4(c, EPOLL_TYPE_UDP_REPLY,
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tgtpif, tgt, fref.data);
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if (uflow->s[TGTSIDE] < 0) {
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flow_dbg_perror(uflow,
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"Couldn't open socket for spliced flow");
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if (pif_is_socket(flow->f.pif[TGTSIDE]))
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if ((uflow->s[TGTSIDE] = udp_flow_sock(c, uflow, TGTSIDE)) < 0)
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goto cancel;
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}
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if (flowside_connect(c, uflow->s[TGTSIDE], tgtpif, tgt) < 0) {
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flow_dbg_perror(uflow, "Couldn't connect flow socket");
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goto cancel;
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}
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/* It's possible, if unlikely, that we could receive some
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* unrelated packets in between the bind() and connect() of this
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* socket. For now we just discard these. We could consider
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* trying to redirect these to an appropriate handler, if we
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* need to.
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*/
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rc = recvmmsg(uflow->s[TGTSIDE], discard, ARRAY_SIZE(discard),
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MSG_DONTWAIT, NULL);
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if (rc >= ARRAY_SIZE(discard)) {
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flow_dbg(uflow,
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"Too many (%d) spurious reply datagrams", rc);
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goto cancel;
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} else if (rc > 0) {
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flow_trace(uflow,
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"Discarded %d spurious reply datagrams", rc);
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} else if (errno != EAGAIN) {
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flow_perror(uflow,
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"Unexpected error discarding datagrams");
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}
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}
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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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