[trafficserver] branch master updated: Add host_override NH option (#9984)

[eze]

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eze pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/trafficserver.git


The following commit(s) were added to refs/heads/master by this push:
     new 04f0ef346f Add host_override NH option (#9984)
04f0ef346f is described below

commit 04f0ef346f1b849556868392ccda4b3a32b673f8
Author: Evan Zelkowitz <e...@apache.org>
AuthorDate: Wed Jul 12 09:04:57 2023 -0600

    Add host_override NH option (#9984)
    
    sets the host header to the upstream parent instead of the original request
---
 doc/admin-guide/files/strategies.yaml.en.rst |  3 +++
 proxy/http/remap/NextHopConsistentHash.cc    |  2 ++
 proxy/http/remap/NextHopRoundRobin.cc        |  1 +
 proxy/http/remap/NextHopSelectionStrategy.cc | 14 ++++++++++++++
 proxy/http/remap/NextHopSelectionStrategy.h  |  3 +++
 5 files changed, 23 insertions(+)

diff --git a/doc/admin-guide/files/strategies.yaml.en.rst 
b/doc/admin-guide/files/strategies.yaml.en.rst
index f5b8443c17..19353d0d48 100644
--- a/doc/admin-guide/files/strategies.yaml.en.rst
+++ b/doc/admin-guide/files/strategies.yaml.en.rst
@@ -230,6 +230,8 @@ Each **strategy** in the list may using the following 
parameters:
     (**self** should only be necessary when the local hostname can only be 
translated to an IP address
     with a DNS lookup.)
 
+- **host_override**: A boolean value that will set the host header to the 
selected parent rather than the original host. **true** sets host header to 
selected parent. **false** (default) leaves the host header untouched.
+
 Example:
 ::
 
@@ -254,6 +256,7 @@ Example:
           - passive
     - strategy: 'strategy-2'
       policy: rr_strict
+      host_override: true
       hash_url: cache
       hash_key: path+query
       go_direct: true
diff --git a/proxy/http/remap/NextHopConsistentHash.cc 
b/proxy/http/remap/NextHopConsistentHash.cc
index fe23dbe854..51a14edc1e 100644
--- a/proxy/http/remap/NextHopConsistentHash.cc
+++ b/proxy/http/remap/NextHopConsistentHash.cc
@@ -496,5 +496,7 @@ NextHopConsistentHash::findNextHop(TSHttpTxn txnp, void 
*ih, time_t now)
              ParentResultStr[result.result]);
   }
 
+  setHostHeader(txnp, result.hostname);
+
   return;
 }
diff --git a/proxy/http/remap/NextHopRoundRobin.cc 
b/proxy/http/remap/NextHopRoundRobin.cc
index f2e872553e..508228e00b 100644
--- a/proxy/http/remap/NextHopRoundRobin.cc
+++ b/proxy/http/remap/NextHopRoundRobin.cc
@@ -171,6 +171,7 @@ NextHopRoundRobin::findNextHop(TSHttpTxn txnp, void *ih, 
time_t now)
       result->last_parent = cur_hst_index;
       result->last_group  = cur_grp_index;
       result->retry       = parentRetry;
+      setHostHeader(txnp, result->hostname);
       ink_assert(result->hostname != nullptr);
       ink_assert(result->port != 0);
       NH_Debug(NH_DEBUG_TAG, "[%" PRIu64 "] Chosen parent = %s.%d", sm_id, 
result->hostname, result->port);
diff --git a/proxy/http/remap/NextHopSelectionStrategy.cc 
b/proxy/http/remap/NextHopSelectionStrategy.cc
index a924c8793e..bb8482a4bc 100644
--- a/proxy/http/remap/NextHopSelectionStrategy.cc
+++ b/proxy/http/remap/NextHopSelectionStrategy.cc
@@ -82,6 +82,10 @@ NextHopSelectionStrategy::NextHopSelectionStrategy(const 
std::string_view &name,
       cache_peer_result = n["cache_peer_result"].as<bool>();
     }
 
+    if (n["host_override"]) {
+      host_override = n["host_override"].as<bool>();
+    }
+
     // failover node.
     YAML::Node failover_node_n = n["failover"];
     if (failover_node_n) {
@@ -255,6 +259,16 @@ NextHopSelectionStrategy::markNextHop(TSHttpTxn txnp, 
const char *hostname, cons
   return passive_health.markNextHop(txnp, hostname, port, status, ih, now);
 }
 
+void
+NextHopSelectionStrategy::setHostHeader(TSHttpTxn txnp, const char *hostname)
+{
+  if (host_override && nullptr != hostname) {
+    HttpSM *sm = reinterpret_cast<HttpSM *>(txnp);
+    sm->t_state.hdr_info.client_request.value_set(MIME_FIELD_HOST, 
MIME_LEN_HOST, hostname, strlen(hostname));
+    NH_Debug(NH_DEBUG_TAG, "[%" PRIu64 "] overriding host header with parent 
%s", sm->sm_id, hostname);
+  }
+}
+
 bool
 NextHopSelectionStrategy::nextHopExists(TSHttpTxn txnp, void *ih)
 {
diff --git a/proxy/http/remap/NextHopSelectionStrategy.h 
b/proxy/http/remap/NextHopSelectionStrategy.h
index 1fe49cb701..d327acddef 100644
--- a/proxy/http/remap/NextHopSelectionStrategy.h
+++ b/proxy/http/remap/NextHopSelectionStrategy.h
@@ -202,6 +202,8 @@ public:
                    const time_t now = 0);
   bool nextHopExists(TSHttpTxn txnp, void *ih = nullptr);
 
+  void setHostHeader(TSHttpTxn txnp, const char *hostname);
+
   virtual ParentRetry_t responseIsRetryable(int64_t sm_id, 
HttpTransact::CurrentInfo &current_info, HTTPStatus response_code);
 
   void retryComplete(TSHttpTxn txn, const char *hostname, const int port);
@@ -211,6 +213,7 @@ public:
   bool parent_is_proxy     = true;
   bool ignore_self_detect  = false;
   bool cache_peer_result   = true;
+  bool host_override       = false;
   NHPolicyType policy_type = NH_UNDEFINED;
   NHSchemeType scheme      = NH_SCHEME_NONE;
   NHRingMode ring_mode     = NH_ALTERNATE_RING;