isc-dhcp relay supports vrf

Author: lucas-li-micas

dockers/docker-dhcp-relay/dhcpv4-relay.agents.j2

@@ -9,21 +9,30 @@
 {% set _dummy = relay_for_ipv4.update({'flag': False}) %}
 [program:isc-dhcpv4-relay-{{ vlan_name }}]
 {# We treat this VLAN as a downstream interface (-id), as we only want to listen for requests #}
-command=/usr/sbin/dhcrelay -d -m discard -a %%h:%%p %%P --name-alias-map-file /tmp/port-name-alias-map.txt -id {{ vlan_name }}
+{% if vlan_name in VLAN_INTERFACE and VLAN_INTERFACE[vlan_name]['vrf_name']|length > 0 %}
+{% set non_default_found = true %}
+{% set vrf_name = VLAN_INTERFACE[vlan_name]['vrf_name'] %}
+{% endif %}
+{% if non_default_found %}
+command=ip vrf exec {{vrf_name}} /usr/sbin/dhcrelay -d -m discard -a %%h:%%p %%P --name-alias-map-file /tmp/port-name-alias-map.txt -id {{ vlan_name -}}
+{% else %}
+command=/usr/sbin/dhcrelay -d -m discard -a %%h:%%p %%P --name-alias-map-file /tmp/port-name-alias-map.txt -id {{ vlan_name -}}
+{% endif -%}
 {#- Dual ToR Option #}
 {% if 'subtype' in DEVICE_METADATA['localhost'] and DEVICE_METADATA['localhost']['subtype'] == 'DualToR' %} -U Loopback0 -dt{% endif -%}
 {#- si option to use intf addr in relay #}
 {% if DEVICE_METADATA['localhost']['deployment_id'] == '8' %} -si{% endif -%}
 {#- We treat all other interfaces as upstream interfaces (-iu), as we only want to listen for replies #}
-{% for (name, prefix) in VLAN_INTERFACE|pfx_filter %}
-{% if prefix | ipv4 and name != vlan_name %} -iu {{ name }}{% endif -%}
-{% endfor %}
-{% for (name, prefix) in INTERFACE|pfx_filter %}
-{% if prefix | ipv4 %} -iu {{ name }}{% endif -%}
-{% endfor %}
-{% for (name, prefix) in PORTCHANNEL_INTERFACE|pfx_filter %}
-{% if prefix | ipv4 %} -iu {{ name }}{% endif -%}
-{% endfor %}
+{% for (name, prefix) in VLAN_INTERFACE|pfx_filter -%}
+{%- if prefix | ipv4 and name != vlan_name %} -iu {{ name }}{% endif -%}
+{%- if prefix | ipv4 and name == vlan_name %} -bind {{ prefix.split('/')[0] }}{% endif -%}
+{%- endfor -%}
+{% for (name, prefix) in INTERFACE|pfx_filter -%}
+{%- if prefix | ipv4 %} -iu {{ name }}{% endif -%}
+{%- endfor -%}
+{% for (name, prefix) in PORTCHANNEL_INTERFACE|pfx_filter -%}
+{%- if prefix | ipv4 %} -iu {{ name }}{% endif -%}
+{%- endfor -%}
 {% for (name, gateway) in VLAN_INTERFACE|get_primary_addr %}
 {% if gateway | ipv4 and name == vlan_name %} -pg {{ gateway }}{% endif -%}
 {% endfor %}

rules/docker-dhcp-relay.mk

@@ -45,7 +45,7 @@ endif
 endif
 
 $(DOCKER_DHCP_RELAY)_CONTAINER_NAME = dhcp_relay
-$(DOCKER_DHCP_RELAY)_CONTAINER_PRIVILEGED = false
+$(DOCKER_DHCP_RELAY)_CONTAINER_PRIVILEGED = true
 $(DOCKER_DHCP_RELAY)_CONTAINER_VOLUMES += /etc/sonic:/etc/sonic:ro
 $(DOCKER_DHCP_RELAY)_CONTAINER_VOLUMES += /etc/localtime:/etc/localtime:ro
 $(DOCKER_DHCP_RELAY)_CONTAINER_TMPFS += /tmp/

src/isc-dhcp/patch/0018-ISC-DHCP-support-dhcp-relay-in-vrf.patch

@@ -0,0 +1,77 @@
+From 58d694a46ad48776c7f20d8f19f453478c1863e2 Mon Sep 17 00:00:00 2001
+From: mirror-bot <mirror@github-actions>
+Date: Mon, 7 Jul 2025 02:10:44 -0500
+Subject: [PATCH] ISC-DHCP-support-dhcp-relay-in-vrf
+
+---
+ common/socket.c  |  8 ++++++++
+ relay/dhcrelay.c | 13 ++++++++++---
+ 2 files changed, 18 insertions(+), 3 deletions(-)
+
+diff --git a/common/socket.c b/common/socket.c
+index 87c62a2..e274d4e 100644
+--- a/common/socket.c
++++ b/common/socket.c
+@@ -48,6 +48,8 @@
+ #include <net/if_dl.h>
+ #include <sys/dlpi.h>
+ #endif
++char uplink_name[IFNAMSIZ];
++struct in_addr bind_ia;
+ 
+ #ifdef USE_SOCKET_FALLBACK
+ # if !defined (USE_SOCKET_SEND)
+@@ -223,6 +225,12 @@ if_register_socket(struct interface_info *info, int family,
+ 		memcpy(&addr->sin_addr,
+ 		       &local_address,
+ 		       sizeof(addr->sin_addr));
++		if (0 <= strlen(uplink_name) && 0 == strcmp(info->name, uplink_name)) {
++		    memcpy(&addr->sin_addr, &bind_ia, sizeof(bind_ia.s_addr));
++		    char str_buf[IFNAMSIZ];
++		    inet_ntop(AF_INET,  &bind_ia, str_buf, sizeof(str_buf));
++		    log_info("bind uplink interface %s to ip:%s success ", uplink_name, str_buf);
++		}
+ #ifdef HAVE_SA_LEN
+ 		addr->sin_len = sizeof(*addr);
+ #endif
+diff --git a/relay/dhcrelay.c b/relay/dhcrelay.c
+index a516829..65e4161 100644
+--- a/relay/dhcrelay.c
++++ b/relay/dhcrelay.c
+@@ -44,7 +44,8 @@ int lexline;
+ int lexchar;
+ char *token_line;
+ char *tlname;
+-
++extern char uplink_name [];
++extern struct in_addr bind_ia; 
+ const char *path_dhcrelay_pid = _PATH_DHCRELAY_PID;
+ isc_boolean_t no_dhcrelay_pid = ISC_FALSE;
+ /* False (default) => we write and use a pid file */
+@@ -508,7 +509,7 @@ main(int argc, char **argv) {
+ 			if (++i == argc) {
+ 				usage(use_noarg, argv[i-1]);
+ 			}
+-
++                        memcpy(uplink_name, argv[i], strlen(argv[i]));
+ 			request_v4_interface(argv[i], INTERFACE_UPSTREAM);
+ 		} else if (!strcmp(argv[i], "-id")) {
+ #ifdef DHCPv6
+@@ -724,7 +725,13 @@ main(int argc, char **argv) {
+ 			local_family = AF_INET;
+ #endif
+ 			enable_support_for_dual_tor = 1;
+- 		} else if (argv[i][0] == '-') {
++ 		} else if (!strcmp(argv[i], "-bind")) {
++		       if (++i == argc)
++			       usage(use_v4command, argv[i-1]);
++		       if (inet_pton(AF_INET, argv[i], &bind_ia)) {
++		               log_info("bind_ia is %s \n", argv[i]);
++		       }
++		} else if (argv[i][0] == '-') {
+ 			usage("Unknown command: %s", argv[i]);
+  		} else {
+ 			struct hostent *he;
+-- 
+2.25.1
+

src/isc-dhcp/patch/series

@@ -15,3 +15,4 @@
 0015-option-to-set-primary-address-in-interface.patch
 0016-Don-t-look-up-the-ifindex-for-fallback.patch
 0017-Register-IO-obj-before-create-fd-watch.patch
+0018-ISC-DHCP-support-dhcp-relay-in-vrf.patch

src/sonic-dhcp-utilities/dhcp_utilities/dhcprelayd/dhcprelayd.py

@@ -274,7 +274,10 @@ def _get_dhcp_relay_config(self):
             cmds = re.findall(r"\[program:((isc-dhcpv4-relay|dhcpmon)-.+)\]\ncommand=(.+)", content)
             for cmd in cmds:
                 key = "dhcpmon:{}".format(cmd[0]) if "dhcpmon" in cmd[0] else cmd[0]
-                res[key] = cmd[2].replace("%%", "%").split(" ")
+                command_str = cmd[2].replace("%%", "%")
+                if key.startswith("isc-dhcpv4-relay"):
+                    command_str = re.sub(r"^ip vrf exec \S+\s*", "", command_str)
+                res[key] = command_str.split(" ")
         return res
 
     def _start_dhcrelay_process(self, new_dhcp_interfaces, dhcp_server_ip, force_kill):