From 82be3c91d5ed996cbf22a4e1c0705085dfa4964a Mon Sep 17 00:00:00 2001
From: Jarrod Johnson <jjohnson2@lenovo.com>
Date: Thu, 22 Aug 2024 10:20:04 -0400
Subject: [PATCH] Add support for relay DHCP

Use the relay DHCP agent information as basis for
subnet comparison instead of self, when present.

Use the candidate prefix length verbatim since the
relay will offer no hint as to the 'proper' prefix
length for the target segment.
---
 .../confluent/discovery/protocols/pxe.py             |  3 ++-
 confluent_server/confluent/netutil.py                | 12 +++++++++---
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/confluent_server/confluent/discovery/protocols/pxe.py b/confluent_server/confluent/discovery/protocols/pxe.py
index 133d8abd..9e88318b 100644
--- a/confluent_server/confluent/discovery/protocols/pxe.py
+++ b/confluent_server/confluent/discovery/protocols/pxe.py
@@ -728,9 +728,10 @@ def reply_dhcp4(node, info, packet, cfg, reqview, httpboot, cfd, profile):
     repview[1:10] = reqview[1:10] # duplicate txid, hwlen, and others
     repview[10:11] = b'\x80'  # always set broadcast
     repview[28:44] = reqview[28:44]  # copy chaddr field
+    relayip = reqview[24:28].tobytes()
     gateway = None
     netmask = None
-    niccfg = netutil.get_nic_config(cfg, node, ifidx=info['netinfo']['ifidx'])
+    niccfg = netutil.get_nic_config(cfg, node, ifidx=info['netinfo']['ifidx'], relayip=relayip)
     nicerr = niccfg.get('error_msg', False)
     if nicerr:
         log.log({'error': nicerr})
diff --git a/confluent_server/confluent/netutil.py b/confluent_server/confluent/netutil.py
index c1a9210a..a852d96c 100644
--- a/confluent_server/confluent/netutil.py
+++ b/confluent_server/confluent/netutil.py
@@ -408,7 +408,7 @@ def noneify(cfgdata):
 # the ip as reported by recvmsg to match the subnet of that net.* interface
 # if switch and port available, that should match.
 def get_nic_config(configmanager, node, ip=None, mac=None, ifidx=None,
-                   serverip=None):
+                   serverip=None, relayipn=b'\x00\x00\x00\x00'):
     """Fetch network configuration parameters for a nic
 
     For a given node and interface, find and retrieve the pertinent network
@@ -489,6 +489,10 @@ def get_nic_config(configmanager, node, ip=None, mac=None, ifidx=None,
         bestsrvbyfam = {}
         for myaddr in myaddrs:
             fam, svrip, prefix = myaddr[:3]
+            if fam == socket.AF_INET and relayipn != b'\x00\x00\x00\x00':
+                bootsvrip = relayipn
+            else:
+                bootsvrip = svrip
             candsrvs.append((fam, svrip, prefix))
             if fam == socket.AF_INET:
                 nver = '4'
@@ -508,6 +512,8 @@ def get_nic_config(configmanager, node, ip=None, mac=None, ifidx=None,
                 candip = cfgbyname[candidate].get('ipv{}_address'.format(nver), None)
                 if candip and '/' in candip:
                     candip, candprefix = candip.split('/')
+                    if fam == socket.AF_INET and relayipn != b'\x00\x00\x00\x00':
+                        prefix = int(candprefix)
                     if int(candprefix) != prefix:
                         continue
                 candgw = cfgbyname[candidate].get('ipv{}_gateway'.format(nver), None)
@@ -515,7 +521,7 @@ def get_nic_config(configmanager, node, ip=None, mac=None, ifidx=None,
                     try:
                         for inf in socket.getaddrinfo(candip, 0, fam, socket.SOCK_STREAM):
                             candipn = socket.inet_pton(fam, inf[-1][0])
-                        if ipn_on_same_subnet(fam, svrip, candipn, prefix):
+                        if ipn_on_same_subnet(fam, bootsvrip, candipn, prefix):
                             bestsrvbyfam[fam] = svrip
                             cfgdata['ipv{}_address'.format(nver)] = candip
                             cfgdata['ipv{}_method'.format(nver)] = ipmethod
@@ -533,7 +539,7 @@ def get_nic_config(configmanager, node, ip=None, mac=None, ifidx=None,
                 elif candgw:
                     for inf in socket.getaddrinfo(candgw, 0, fam, socket.SOCK_STREAM):
                         candgwn = socket.inet_pton(fam, inf[-1][0])
-                    if ipn_on_same_subnet(fam, svrip, candgwn, prefix):
+                    if ipn_on_same_subnet(fam, bootsvrip, candgwn, prefix):
                         candgws.append((fam, candgwn, prefix))
         if foundaddr:
             return noneify(cfgdata)