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authorJakub Kicinski <kuba@kernel.org>2024-04-23 11:35:41 -0700
committerJakub Kicinski <kuba@kernel.org>2024-04-24 20:15:45 -0700
commit6b88ce902f0bdcb3694a6ceddc8b3d0b40db3772 (patch)
treefe004b46fad8cbb08507761b6985ee10e3a8d003 /tools/testing/selftests/net/nat6to4.c
parent2fa809b90617817fec2802c7cfaeb2c66fd04c2b (diff)
selftests: net: name bpf objects consistently and simplify Makefile
The BPF sources moved with bpf_offload.py have a suffix of .bpf.c which seems to be useful convention. Rename the 2 other BPF sources we had. Use wildcard in the Makefile, since we can match all those files easily now. Link: https://lore.kernel.org/r/20240423183542.3807234-2-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'tools/testing/selftests/net/nat6to4.c')
-rw-r--r--tools/testing/selftests/net/nat6to4.c285
1 files changed, 0 insertions, 285 deletions
diff --git a/tools/testing/selftests/net/nat6to4.c b/tools/testing/selftests/net/nat6to4.c
deleted file mode 100644
index ac54c36b25fc..000000000000
--- a/tools/testing/selftests/net/nat6to4.c
+++ /dev/null
@@ -1,285 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * This code is taken from the Android Open Source Project and the author
- * (Maciej Żenczykowski) has gave permission to relicense it under the
- * GPLv2. Therefore this program is free software;
- * You can redistribute it and/or modify it under the terms of the GNU
- * General Public License version 2 as published by the Free Software
- * Foundation
-
- * The original headers, including the original license headers, are
- * included below for completeness.
- *
- * Copyright (C) 2019 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-#include <linux/bpf.h>
-#include <linux/if.h>
-#include <linux/if_ether.h>
-#include <linux/if_packet.h>
-#include <linux/in.h>
-#include <linux/in6.h>
-#include <linux/ip.h>
-#include <linux/ipv6.h>
-#include <linux/pkt_cls.h>
-#include <linux/swab.h>
-#include <stdbool.h>
-#include <stdint.h>
-
-
-#include <linux/udp.h>
-
-#include <bpf/bpf_helpers.h>
-#include <bpf/bpf_endian.h>
-
-#define IP_DF 0x4000 // Flag: "Don't Fragment"
-
-SEC("schedcls/ingress6/nat_6")
-int sched_cls_ingress6_nat_6_prog(struct __sk_buff *skb)
-{
- const int l2_header_size = sizeof(struct ethhdr);
- void *data = (void *)(long)skb->data;
- const void *data_end = (void *)(long)skb->data_end;
- const struct ethhdr * const eth = data; // used iff is_ethernet
- const struct ipv6hdr * const ip6 = (void *)(eth + 1);
-
- // Require ethernet dst mac address to be our unicast address.
- if (skb->pkt_type != PACKET_HOST)
- return TC_ACT_OK;
-
- // Must be meta-ethernet IPv6 frame
- if (skb->protocol != bpf_htons(ETH_P_IPV6))
- return TC_ACT_OK;
-
- // Must have (ethernet and) ipv6 header
- if (data + l2_header_size + sizeof(*ip6) > data_end)
- return TC_ACT_OK;
-
- // Ethertype - if present - must be IPv6
- if (eth->h_proto != bpf_htons(ETH_P_IPV6))
- return TC_ACT_OK;
-
- // IP version must be 6
- if (ip6->version != 6)
- return TC_ACT_OK;
- // Maximum IPv6 payload length that can be translated to IPv4
- if (bpf_ntohs(ip6->payload_len) > 0xFFFF - sizeof(struct iphdr))
- return TC_ACT_OK;
- switch (ip6->nexthdr) {
- case IPPROTO_TCP: // For TCP & UDP the checksum neutrality of the chosen IPv6
- case IPPROTO_UDP: // address means there is no need to update their checksums.
- case IPPROTO_GRE: // We do not need to bother looking at GRE/ESP headers,
- case IPPROTO_ESP: // since there is never a checksum to update.
- break;
- default: // do not know how to handle anything else
- return TC_ACT_OK;
- }
-
- struct ethhdr eth2; // used iff is_ethernet
-
- eth2 = *eth; // Copy over the ethernet header (src/dst mac)
- eth2.h_proto = bpf_htons(ETH_P_IP); // But replace the ethertype
-
- struct iphdr ip = {
- .version = 4, // u4
- .ihl = sizeof(struct iphdr) / sizeof(__u32), // u4
- .tos = (ip6->priority << 4) + (ip6->flow_lbl[0] >> 4), // u8
- .tot_len = bpf_htons(bpf_ntohs(ip6->payload_len) + sizeof(struct iphdr)), // u16
- .id = 0, // u16
- .frag_off = bpf_htons(IP_DF), // u16
- .ttl = ip6->hop_limit, // u8
- .protocol = ip6->nexthdr, // u8
- .check = 0, // u16
- .saddr = 0x0201a8c0, // u32
- .daddr = 0x0101a8c0, // u32
- };
-
- // Calculate the IPv4 one's complement checksum of the IPv4 header.
- __wsum sum4 = 0;
-
- for (int i = 0; i < sizeof(ip) / sizeof(__u16); ++i)
- sum4 += ((__u16 *)&ip)[i];
-
- // Note that sum4 is guaranteed to be non-zero by virtue of ip.version == 4
- sum4 = (sum4 & 0xFFFF) + (sum4 >> 16); // collapse u32 into range 1 .. 0x1FFFE
- sum4 = (sum4 & 0xFFFF) + (sum4 >> 16); // collapse any potential carry into u16
- ip.check = (__u16)~sum4; // sum4 cannot be zero, so this is never 0xFFFF
-
- // Calculate the *negative* IPv6 16-bit one's complement checksum of the IPv6 header.
- __wsum sum6 = 0;
- // We'll end up with a non-zero sum due to ip6->version == 6 (which has '0' bits)
- for (int i = 0; i < sizeof(*ip6) / sizeof(__u16); ++i)
- sum6 += ~((__u16 *)ip6)[i]; // note the bitwise negation
-
- // Note that there is no L4 checksum update: we are relying on the checksum neutrality
- // of the ipv6 address chosen by netd's ClatdController.
-
- // Packet mutations begin - point of no return, but if this first modification fails
- // the packet is probably still pristine, so let clatd handle it.
- if (bpf_skb_change_proto(skb, bpf_htons(ETH_P_IP), 0))
- return TC_ACT_OK;
- bpf_csum_update(skb, sum6);
-
- data = (void *)(long)skb->data;
- data_end = (void *)(long)skb->data_end;
- if (data + l2_header_size + sizeof(struct iphdr) > data_end)
- return TC_ACT_SHOT;
-
- struct ethhdr *new_eth = data;
-
- // Copy over the updated ethernet header
- *new_eth = eth2;
-
- // Copy over the new ipv4 header.
- *(struct iphdr *)(new_eth + 1) = ip;
- return bpf_redirect(skb->ifindex, BPF_F_INGRESS);
-}
-
-SEC("schedcls/egress4/snat4")
-int sched_cls_egress4_snat4_prog(struct __sk_buff *skb)
-{
- const int l2_header_size = sizeof(struct ethhdr);
- void *data = (void *)(long)skb->data;
- const void *data_end = (void *)(long)skb->data_end;
- const struct ethhdr *const eth = data; // used iff is_ethernet
- const struct iphdr *const ip4 = (void *)(eth + 1);
-
- // Must be meta-ethernet IPv4 frame
- if (skb->protocol != bpf_htons(ETH_P_IP))
- return TC_ACT_OK;
-
- // Must have ipv4 header
- if (data + l2_header_size + sizeof(struct ipv6hdr) > data_end)
- return TC_ACT_OK;
-
- // Ethertype - if present - must be IPv4
- if (eth->h_proto != bpf_htons(ETH_P_IP))
- return TC_ACT_OK;
-
- // IP version must be 4
- if (ip4->version != 4)
- return TC_ACT_OK;
-
- // We cannot handle IP options, just standard 20 byte == 5 dword minimal IPv4 header
- if (ip4->ihl != 5)
- return TC_ACT_OK;
-
- // Maximum IPv6 payload length that can be translated to IPv4
- if (bpf_htons(ip4->tot_len) > 0xFFFF - sizeof(struct ipv6hdr))
- return TC_ACT_OK;
-
- // Calculate the IPv4 one's complement checksum of the IPv4 header.
- __wsum sum4 = 0;
-
- for (int i = 0; i < sizeof(*ip4) / sizeof(__u16); ++i)
- sum4 += ((__u16 *)ip4)[i];
-
- // Note that sum4 is guaranteed to be non-zero by virtue of ip4->version == 4
- sum4 = (sum4 & 0xFFFF) + (sum4 >> 16); // collapse u32 into range 1 .. 0x1FFFE
- sum4 = (sum4 & 0xFFFF) + (sum4 >> 16); // collapse any potential carry into u16
- // for a correct checksum we should get *a* zero, but sum4 must be positive, ie 0xFFFF
- if (sum4 != 0xFFFF)
- return TC_ACT_OK;
-
- // Minimum IPv4 total length is the size of the header
- if (bpf_ntohs(ip4->tot_len) < sizeof(*ip4))
- return TC_ACT_OK;
-
- // We are incapable of dealing with IPv4 fragments
- if (ip4->frag_off & ~bpf_htons(IP_DF))
- return TC_ACT_OK;
-
- switch (ip4->protocol) {
- case IPPROTO_TCP: // For TCP & UDP the checksum neutrality of the chosen IPv6
- case IPPROTO_GRE: // address means there is no need to update their checksums.
- case IPPROTO_ESP: // We do not need to bother looking at GRE/ESP headers,
- break; // since there is never a checksum to update.
-
- case IPPROTO_UDP: // See above comment, but must also have UDP header...
- if (data + sizeof(*ip4) + sizeof(struct udphdr) > data_end)
- return TC_ACT_OK;
- const struct udphdr *uh = (const struct udphdr *)(ip4 + 1);
- // If IPv4/UDP checksum is 0 then fallback to clatd so it can calculate the
- // checksum. Otherwise the network or more likely the NAT64 gateway might
- // drop the packet because in most cases IPv6/UDP packets with a zero checksum
- // are invalid. See RFC 6935. TODO: calculate checksum via bpf_csum_diff()
- if (!uh->check)
- return TC_ACT_OK;
- break;
-
- default: // do not know how to handle anything else
- return TC_ACT_OK;
- }
- struct ethhdr eth2; // used iff is_ethernet
-
- eth2 = *eth; // Copy over the ethernet header (src/dst mac)
- eth2.h_proto = bpf_htons(ETH_P_IPV6); // But replace the ethertype
-
- struct ipv6hdr ip6 = {
- .version = 6, // __u8:4
- .priority = ip4->tos >> 4, // __u8:4
- .flow_lbl = {(ip4->tos & 0xF) << 4, 0, 0}, // __u8[3]
- .payload_len = bpf_htons(bpf_ntohs(ip4->tot_len) - 20), // __be16
- .nexthdr = ip4->protocol, // __u8
- .hop_limit = ip4->ttl, // __u8
- };
- ip6.saddr.in6_u.u6_addr32[0] = bpf_htonl(0x20010db8);
- ip6.saddr.in6_u.u6_addr32[1] = 0;
- ip6.saddr.in6_u.u6_addr32[2] = 0;
- ip6.saddr.in6_u.u6_addr32[3] = bpf_htonl(1);
- ip6.daddr.in6_u.u6_addr32[0] = bpf_htonl(0x20010db8);
- ip6.daddr.in6_u.u6_addr32[1] = 0;
- ip6.daddr.in6_u.u6_addr32[2] = 0;
- ip6.daddr.in6_u.u6_addr32[3] = bpf_htonl(2);
-
- // Calculate the IPv6 16-bit one's complement checksum of the IPv6 header.
- __wsum sum6 = 0;
- // We'll end up with a non-zero sum due to ip6.version == 6
- for (int i = 0; i < sizeof(ip6) / sizeof(__u16); ++i)
- sum6 += ((__u16 *)&ip6)[i];
-
- // Packet mutations begin - point of no return, but if this first modification fails
- // the packet is probably still pristine, so let clatd handle it.
- if (bpf_skb_change_proto(skb, bpf_htons(ETH_P_IPV6), 0))
- return TC_ACT_OK;
-
- // This takes care of updating the skb->csum field for a CHECKSUM_COMPLETE packet.
- // In such a case, skb->csum is a 16-bit one's complement sum of the entire payload,
- // thus we need to subtract out the ipv4 header's sum, and add in the ipv6 header's sum.
- // However, we've already verified the ipv4 checksum is correct and thus 0.
- // Thus we only need to add the ipv6 header's sum.
- //
- // bpf_csum_update() always succeeds if the skb is CHECKSUM_COMPLETE and returns an error
- // (-ENOTSUPP) if it isn't. So we just ignore the return code (see above for more details).
- bpf_csum_update(skb, sum6);
-
- // bpf_skb_change_proto() invalidates all pointers - reload them.
- data = (void *)(long)skb->data;
- data_end = (void *)(long)skb->data_end;
-
- // I cannot think of any valid way for this error condition to trigger, however I do
- // believe the explicit check is required to keep the in kernel ebpf verifier happy.
- if (data + l2_header_size + sizeof(ip6) > data_end)
- return TC_ACT_SHOT;
-
- struct ethhdr *new_eth = data;
-
- // Copy over the updated ethernet header
- *new_eth = eth2;
- // Copy over the new ipv4 header.
- *(struct ipv6hdr *)(new_eth + 1) = ip6;
- return TC_ACT_OK;
-}
-
-char _license[] SEC("license") = ("GPL");