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The following commit(s) were added to refs/heads/master by this push:
new 7810e6b TS-4116: DNS failure prohibits use of client target
address (#599)
7810e6b is described below
commit 7810e6bd68fd1b542a297af3896f9412b2586aa9
Author: Uri Shachar <uri@fire.glass>
AuthorDate: Sun Apr 24 23:34:15 2016 +0300
TS-4116: DNS failure prohibits use of client target address (#599)
Refactor handling of use_client_target_addr=1 when DNS resolving fails
---
proxy/http/HttpSM.cc | 66 ++++++++++++++++++----------------------------
proxy/http/HttpTransact.cc | 7 +++--
2 files changed, 31 insertions(+), 42 deletions(-)
diff --git a/proxy/http/HttpSM.cc b/proxy/http/HttpSM.cc
index b8b2ef0..6487b16 100644
--- a/proxy/http/HttpSM.cc
+++ b/proxy/http/HttpSM.cc
@@ -2055,39 +2055,37 @@ HttpSM::process_srv_info(HostDBInfo *r)
void
HttpSM::process_hostdb_info(HostDBInfo *r)
{
+ sockaddr const *client_addr = NULL;
+ bool use_client_addr = t_state.http_config_param->use_client_target_addr ==
1 && t_state.client_info.is_transparent &&
+ t_state.dns_info.os_addr_style ==
HttpTransact::DNSLookupInfo::OS_ADDR_TRY_DEFAULT;
+ if (use_client_addr) {
+ client_addr =
t_state.state_machine->ua_session->get_netvc()->get_local_addr();
+ // Regardless of whether the client address matches the DNS record or not,
+ // we want to use that address. Therefore, we copy over the client address
+ // info and skip the assignment from the DNS cache
+ ats_ip_copy(t_state.host_db_info.ip(), client_addr);
+ t_state.dns_info.os_addr_style =
HttpTransact::DNSLookupInfo::OS_ADDR_TRY_CLIENT;
+ t_state.dns_info.lookup_success = true;
+ // Leave ret unassigned, so we don't overwrite the host_db_info
+ }
+
if (r && !r->failed()) {
ink_time_t now = ink_cluster_time();
HostDBInfo *ret = NULL;
t_state.dns_info.lookup_success = true;
t_state.dns_info.lookup_validated = true;
- if (r->round_robin) {
- // if use_client_target_addr is set, make sure the client
- // addr sits in the pool
- if (t_state.http_config_param->use_client_target_addr == 1 &&
t_state.client_info.is_transparent &&
- t_state.dns_info.os_addr_style ==
HttpTransact::DNSLookupInfo::OS_ADDR_TRY_DEFAULT) {
- HostDBRoundRobin *rr = r->rr();
- sockaddr const *addr =
t_state.state_machine->ua_session->get_netvc()->get_local_addr();
-
- if (rr && rr->find_ip(addr) == NULL) {
- // The client specified server address does not appear
- // in the DNS pool
- DebugSM("http",
- "use_client_target_addr == 1. Client specified address is
not in the pool. Client address is not validated.");
- t_state.dns_info.lookup_validated = false;
- }
- // Even if we did find the client specified address in the pool,
- // We want to make sure that that address is used and not some
- // other address in the DNS set.
- // Copy over the client information and give up on the lookup
- ats_ip_copy(t_state.host_db_info.ip(), addr);
- t_state.dns_info.os_addr_style =
HttpTransact::DNSLookupInfo::OS_ADDR_TRY_CLIENT;
+
+ HostDBRoundRobin *rr = r->round_robin ? r->rr() : NULL;
+ if (rr) {
+ // if use_client_target_addr is set, make sure the client addr is in the
results pool
+ if (use_client_addr && rr->find_ip(client_addr) == NULL) {
+ DebugSM("http", "use_client_target_addr == 1. Client specified address
is not in the pool, not validated.");
+ t_state.dns_info.lookup_validated = false;
} else {
// Since the time elapsed between current time and client_request_time
// may be very large, we cannot use client_request_time to approximate
// current time when calling select_best_http().
- HostDBRoundRobin *rr = r->rr();
ret = rr->select_best_http(&t_state.client_info.src_addr.sa, now,
static_cast<int>(t_state.txn_conf->down_server_timeout));
-
// set the srv target`s last_failure
if (t_state.dns_info.srv_lookup_success) {
uint32_t last_failure = 0xFFFFFFFF;
@@ -2106,22 +2104,9 @@ HttpSM::process_hostdb_info(HostDBInfo *r)
}
}
} else {
- if (t_state.http_config_param->use_client_target_addr == 1 &&
t_state.client_info.is_transparent &&
- t_state.dns_info.os_addr_style ==
HttpTransact::DNSLookupInfo::OS_ADDR_TRY_DEFAULT) {
- // Compare the client specified address against the looked up address
- sockaddr const *addr =
t_state.state_machine->ua_session->get_netvc()->get_local_addr();
- if (!ats_ip_addr_eq(addr, &r->data.ip.sa)) {
- DebugSM("http", "use_client_target_addr == 1. Comparing single
addresses failed. Client address is not validated.");
- t_state.dns_info.lookup_validated = false;
- }
- // Regardless of whether the client address matches the DNS
- // record or not, we want to use that address. Therefore,
- // we copy over the client address info and skip the assignment
- // from the DNS cache
- ats_ip_copy(t_state.host_db_info.ip(), addr);
- t_state.dns_info.os_addr_style =
HttpTransact::DNSLookupInfo::OS_ADDR_TRY_CLIENT;
-
- // Leave ret unassigned, so we don't overwrite the host_db_info
+ if (use_client_addr && !ats_ip_addr_eq(client_addr, &r->data.ip.sa)) {
+ DebugSM("http", "use_client_target_addr == 1. Comparing single
addresses failed, not validated.");
+ t_state.dns_info.lookup_validated = false;
} else {
ret = r;
}
@@ -2134,7 +2119,8 @@ HttpSM::process_hostdb_info(HostDBInfo *r)
} else {
DebugSM("http", "[%" PRId64 "] DNS lookup failed for '%s'", sm_id,
t_state.dns_info.lookup_name);
- t_state.dns_info.lookup_success = false;
+ if (!use_client_addr)
+ t_state.dns_info.lookup_success = false;
t_state.host_db_info.app.allotment.application1 = 0;
t_state.host_db_info.app.allotment.application2 = 0;
ink_assert(!t_state.host_db_info.round_robin);
diff --git a/proxy/http/HttpTransact.cc b/proxy/http/HttpTransact.cc
index aa3f143..06bfe78 100644
--- a/proxy/http/HttpTransact.cc
+++ b/proxy/http/HttpTransact.cc
@@ -1701,10 +1701,13 @@ HttpTransact::OSDNSLookup(State *s)
case EXPANSION_FAILED:
case DNS_ATTEMPTS_EXHAUSTED:
if (DNSLookupInfo::OS_ADDR_TRY_HOSTDB == s->dns_info.os_addr_style) {
- // No HostDB data, just keep on with the CTA.
+ /*
+ * We tried to connect to client target address, failed and tried to
use a different addr
+ * No HostDB data, just keep on with the CTA.
+ */
s->dns_info.lookup_success = true;
s->dns_info.os_addr_style = DNSLookupInfo::OS_ADDR_USE_CLIENT;
- DebugTxn("http_seq", "[HttpTransact::OSDNSLookup] DNS lookup
unsuccessful reverting to force client target address use");
+ DebugTxn("http_seq", "[HttpTransact::OSDNSLookup] DNS lookup
unsuccessful, using client target address");
} else {
if (host_name_expansion == EXPANSION_NOT_ALLOWED) {
// config file doesn't allow automatic expansion of host names
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