From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Tue, 4 Feb 2025 15:46:39 +0000 (+0100)
Subject: dnsdist: Make hard-coded values configurable in xdp.py
X-Git-Tag: dnsdist-2.0.0-alpha1~124^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=030cb125e3dfaedd1277ff913b6d825232071693;p=thirdparty%2Fpdns.git

dnsdist: Make hard-coded values configurable in xdp.py

- Maximum size of eBPF maps
- Number of network queues in XSK mode
---

diff --git a/contrib/xdp-filter.ebpf.src b/contrib/xdp-filter.ebpf.src
index ec0d07145d..f25ba2c08e 100644
--- a/contrib/xdp-filter.ebpf.src
+++ b/contrib/xdp-filter.ebpf.src
@@ -2,9 +2,17 @@
 
 #define DISABLE_LOGGING 1
 
-BPF_TABLE_PINNED("hash", uint32_t, struct map_value, v4filter, 1024, "/sys/fs/bpf/dnsdist/addr-v4");
-BPF_TABLE_PINNED("hash", struct in6_addr, struct map_value, v6filter, 1024, "/sys/fs/bpf/dnsdist/addr-v6");
-BPF_TABLE_PINNED("hash", struct dns_qname, struct map_value, qnamefilter, 1024, "/sys/fs/bpf/dnsdist/qnames");
+#if !defined(DDIST_MAPS_SIZE)
+#define DDIST_MAPS_SIZE 1024
+#endif /* DDIST_MAPS_SIZE */
+
+#if !defined(DDIST_MAX_NUMBER_OF_QUEUES)
+#define DDIST_MAX_NUMBER_OF_QUEUES 64
+#endif /* DDIST_MAX_NUMBER_OF_QUEUES */
+
+BPF_TABLE_PINNED("hash", uint32_t, struct map_value, v4filter, DDIST_MAPS_SIZE, "/sys/fs/bpf/dnsdist/addr-v4");
+BPF_TABLE_PINNED("hash", struct in6_addr, struct map_value, v6filter, DDIST_MAPS_SIZE, "/sys/fs/bpf/dnsdist/addr-v6");
+BPF_TABLE_PINNED("hash", struct dns_qname, struct map_value, qnamefilter, DDIST_MAPS_SIZE, "/sys/fs/bpf/dnsdist/qnames");
 #ifndef DISABLE_LOGGING
 BPF_TABLE_PINNED("prog", int, int, progsarray, 2, "/sys/fs/bpf/dnsdist/progs");
 #endif /* DISABLE_LOGGING */
@@ -18,8 +26,8 @@ BPF_TABLE_PINNED("prog", int, int, progsarray, 2, "/sys/fs/bpf/dnsdist/progs");
   BPF_F_TABLE(_table_type ":" _pinned, _key_type, _leaf_type, _name, _max_entries, _flags)
 #endif
 
-BPF_TABLE_PINNED7("lpm_trie", struct CIDR4, struct map_value, cidr4filter, 1024, "/sys/fs/bpf/dnsdist/cidr4", BPF_F_NO_PREALLOC);
-BPF_TABLE_PINNED7("lpm_trie", struct CIDR6, struct map_value, cidr6filter, 1024, "/sys/fs/bpf/dnsdist/cidr6", BPF_F_NO_PREALLOC);
+BPF_TABLE_PINNED7("lpm_trie", struct CIDR4, struct map_value, cidr4filter, DDIST_MAPS_SIZE, "/sys/fs/bpf/dnsdist/cidr4", BPF_F_NO_PREALLOC);
+BPF_TABLE_PINNED7("lpm_trie", struct CIDR6, struct map_value, cidr6filter, DDIST_MAPS_SIZE, "/sys/fs/bpf/dnsdist/cidr6", BPF_F_NO_PREALLOC);
 
 #ifdef UseXsk
 #define BPF_XSKMAP_PIN(_name, _max_entries, _pinned) \
@@ -34,9 +42,9 @@ BPF_TABLE_PINNED7("lpm_trie", struct CIDR6, struct map_value, cidr6filter, 1024,
   };                                                 \
   __attribute__((section("maps/xskmap:" _pinned))) struct _name##_table_t _name = {.max_entries = (_max_entries)}
 
-BPF_XSKMAP_PIN(xsk_map, 16, "/sys/fs/bpf/dnsdist/xskmap");
-BPF_TABLE_PINNED("hash", struct IPv4AndPort, bool, xskDestinationsV4, 1024, "/sys/fs/bpf/dnsdist/xsk-destinations-v4");
-BPF_TABLE_PINNED("hash", struct IPv6AndPort, bool, xskDestinationsV6, 1024, "/sys/fs/bpf/dnsdist/xsk-destinations-v6");
+BPF_XSKMAP_PIN(xsk_map, DDIST_MAX_NUMBER_OF_QUEUES, "/sys/fs/bpf/dnsdist/xskmap");
+BPF_TABLE_PINNED("hash", struct IPv4AndPort, bool, xskDestinationsV4, DDIST_MAPS_SIZE, "/sys/fs/bpf/dnsdist/xsk-destinations-v4");
+BPF_TABLE_PINNED("hash", struct IPv6AndPort, bool, xskDestinationsV6, DDIST_MAPS_SIZE, "/sys/fs/bpf/dnsdist/xsk-destinations-v6");
 #endif /* UseXsk */
 
 #define COMPARE_PORT(x, p) ((x) == bpf_htons(p))
diff --git a/contrib/xdp.py b/contrib/xdp.py
index 46725e8fd6..9ad0124931 100644
--- a/contrib/xdp.py
+++ b/contrib/xdp.py
@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
 import argparse
 import ctypes as ct
-import netaddr
 import socket
 
+import netaddr
 from bcc import BPF
 
 # Constants
@@ -26,14 +26,17 @@ blocked_qnames = [("localhost", "A", DROP_ACTION), ("test.com", "*", TC_ACTION)]
 
 # Main
 parser = argparse.ArgumentParser(description='XDP helper for DNSDist')
-parser.add_argument('--xsk', action='store_true', help='Enable XSK (AF_XDP) mode', default=False)
 parser.add_argument('--interface', '-i', type=str, default='eth0', help='The interface on which the filter will be attached')
+parser.add_argument('--maps-size', '-m', type=int, default=1024, help='Maximum number of entries in the eBPF maps')
+parser.add_argument('--number-of-queues', '-q', type=int, default=64, help='Maximum number of network queues in XSK (AF_XDP) mode')
+parser.add_argument('--xsk', action='store_true', help='Enable XSK (AF_XDP) mode', default=False)
 
 parameters = parser.parse_args()
-cflag = []
+cflag = [f'-DDDIST_MAX_NUMBER_OF_QUEUES={parameters.number_of_queues}',
+         f'-DDDIST_MAPS_SIZE={parameters.maps_size}']
 if parameters.xsk:
   print(f'Enabling XSK (AF_XDP) on {parameters.interface}..')
-  cflag.append("-DUseXsk")
+  cflag.append('-DUseXsk')
 else:
   Ports = [53]
   portsStr = ', '.join(str(port) for port in Ports)
@@ -51,6 +54,7 @@ v6filter = xdp.get_table("v6filter")
 cidr4filter = xdp.get_table("cidr4filter")
 cidr6filter = xdp.get_table("cidr6filter")
 qnamefilter = xdp.get_table("qnamefilter")
+xskDestinations = None
 
 if parameters.xsk:
   xskDestinations = xdp.get_table("xskDestinationsV4")