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3e689141e6
Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure that all
includes of exported libbpf header files (those that are exported on 'make
install' of the library) use bracketed includes instead of quoted.
To not break the build, keep the old include path until everything has been
changed to the new one; a subsequent patch will remove that.
Fixes: 6910d7d386
("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560568.1683545.9649335788846513446.stgit@toke.dk
292 lines
7.3 KiB
C
292 lines
7.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0
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* Copyright(c) 2018 Jesper Dangaard Brouer.
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*
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* XDP/TC VLAN manipulation example
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*
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* GOTCHA: Remember to disable NIC hardware offloading of VLANs,
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* else the VLAN tags are NOT inlined in the packet payload:
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*
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* # ethtool -K ixgbe2 rxvlan off
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*
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* Verify setting:
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* # ethtool -k ixgbe2 | grep rx-vlan-offload
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* rx-vlan-offload: off
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*
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*/
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#include <stddef.h>
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#include <stdbool.h>
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#include <string.h>
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#include <linux/bpf.h>
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#include <linux/if_ether.h>
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#include <linux/if_vlan.h>
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#include <linux/in.h>
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#include <linux/pkt_cls.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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/* linux/if_vlan.h have not exposed this as UAPI, thus mirror some here
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*
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* struct vlan_hdr - vlan header
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* @h_vlan_TCI: priority and VLAN ID
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* @h_vlan_encapsulated_proto: packet type ID or len
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*/
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struct _vlan_hdr {
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__be16 h_vlan_TCI;
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__be16 h_vlan_encapsulated_proto;
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};
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#define VLAN_PRIO_MASK 0xe000 /* Priority Code Point */
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#define VLAN_PRIO_SHIFT 13
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#define VLAN_CFI_MASK 0x1000 /* Canonical Format Indicator */
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#define VLAN_TAG_PRESENT VLAN_CFI_MASK
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#define VLAN_VID_MASK 0x0fff /* VLAN Identifier */
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#define VLAN_N_VID 4096
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struct parse_pkt {
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__u16 l3_proto;
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__u16 l3_offset;
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__u16 vlan_outer;
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__u16 vlan_inner;
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__u8 vlan_outer_offset;
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__u8 vlan_inner_offset;
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};
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char _license[] SEC("license") = "GPL";
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static __always_inline
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bool parse_eth_frame(struct ethhdr *eth, void *data_end, struct parse_pkt *pkt)
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{
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__u16 eth_type;
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__u8 offset;
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offset = sizeof(*eth);
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/* Make sure packet is large enough for parsing eth + 2 VLAN headers */
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if ((void *)eth + offset + (2*sizeof(struct _vlan_hdr)) > data_end)
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return false;
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eth_type = eth->h_proto;
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/* Handle outer VLAN tag */
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if (eth_type == bpf_htons(ETH_P_8021Q)
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|| eth_type == bpf_htons(ETH_P_8021AD)) {
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struct _vlan_hdr *vlan_hdr;
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vlan_hdr = (void *)eth + offset;
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pkt->vlan_outer_offset = offset;
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pkt->vlan_outer = bpf_ntohs(vlan_hdr->h_vlan_TCI)
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& VLAN_VID_MASK;
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eth_type = vlan_hdr->h_vlan_encapsulated_proto;
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offset += sizeof(*vlan_hdr);
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}
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/* Handle inner (double) VLAN tag */
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if (eth_type == bpf_htons(ETH_P_8021Q)
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|| eth_type == bpf_htons(ETH_P_8021AD)) {
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struct _vlan_hdr *vlan_hdr;
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vlan_hdr = (void *)eth + offset;
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pkt->vlan_inner_offset = offset;
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pkt->vlan_inner = bpf_ntohs(vlan_hdr->h_vlan_TCI)
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& VLAN_VID_MASK;
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eth_type = vlan_hdr->h_vlan_encapsulated_proto;
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offset += sizeof(*vlan_hdr);
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}
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pkt->l3_proto = bpf_ntohs(eth_type); /* Convert to host-byte-order */
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pkt->l3_offset = offset;
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return true;
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}
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/* Hint, VLANs are choosen to hit network-byte-order issues */
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#define TESTVLAN 4011 /* 0xFAB */
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// #define TO_VLAN 4000 /* 0xFA0 (hint 0xOA0 = 160) */
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SEC("xdp_drop_vlan_4011")
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int xdp_prognum0(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct parse_pkt pkt = { 0 };
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if (!parse_eth_frame(data, data_end, &pkt))
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return XDP_ABORTED;
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/* Drop specific VLAN ID example */
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if (pkt.vlan_outer == TESTVLAN)
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return XDP_ABORTED;
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/*
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* Using XDP_ABORTED makes it possible to record this event,
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* via tracepoint xdp:xdp_exception like:
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* # perf record -a -e xdp:xdp_exception
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* # perf script
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*/
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return XDP_PASS;
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}
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/*
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Commands to setup VLAN on Linux to test packets gets dropped:
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export ROOTDEV=ixgbe2
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export VLANID=4011
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ip link add link $ROOTDEV name $ROOTDEV.$VLANID type vlan id $VLANID
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ip link set dev $ROOTDEV.$VLANID up
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ip link set dev $ROOTDEV mtu 1508
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ip addr add 100.64.40.11/24 dev $ROOTDEV.$VLANID
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Load prog with ip tool:
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ip link set $ROOTDEV xdp off
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ip link set $ROOTDEV xdp object xdp_vlan01_kern.o section xdp_drop_vlan_4011
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*/
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/* Changing VLAN to zero, have same practical effect as removing the VLAN. */
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#define TO_VLAN 0
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SEC("xdp_vlan_change")
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int xdp_prognum1(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct parse_pkt pkt = { 0 };
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if (!parse_eth_frame(data, data_end, &pkt))
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return XDP_ABORTED;
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/* Change specific VLAN ID */
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if (pkt.vlan_outer == TESTVLAN) {
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struct _vlan_hdr *vlan_hdr = data + pkt.vlan_outer_offset;
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/* Modifying VLAN, preserve top 4 bits */
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vlan_hdr->h_vlan_TCI =
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bpf_htons((bpf_ntohs(vlan_hdr->h_vlan_TCI) & 0xf000)
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| TO_VLAN);
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}
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return XDP_PASS;
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}
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/*
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* Show XDP+TC can cooperate, on creating a VLAN rewriter.
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* 1. Create a XDP prog that can "pop"/remove a VLAN header.
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* 2. Create a TC-bpf prog that egress can add a VLAN header.
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*/
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#ifndef ETH_ALEN /* Ethernet MAC address length */
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#define ETH_ALEN 6 /* bytes */
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#endif
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#define VLAN_HDR_SZ 4 /* bytes */
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SEC("xdp_vlan_remove_outer")
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int xdp_prognum2(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct parse_pkt pkt = { 0 };
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char *dest;
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if (!parse_eth_frame(data, data_end, &pkt))
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return XDP_ABORTED;
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/* Skip packet if no outer VLAN was detected */
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if (pkt.vlan_outer_offset == 0)
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return XDP_PASS;
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/* Moving Ethernet header, dest overlap with src, memmove handle this */
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dest = data;
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dest+= VLAN_HDR_SZ;
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/*
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* Notice: Taking over vlan_hdr->h_vlan_encapsulated_proto, by
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* only moving two MAC addrs (12 bytes), not overwriting last 2 bytes
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*/
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__builtin_memmove(dest, data, ETH_ALEN * 2);
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/* Note: LLVM built-in memmove inlining require size to be constant */
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/* Move start of packet header seen by Linux kernel stack */
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bpf_xdp_adjust_head(ctx, VLAN_HDR_SZ);
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return XDP_PASS;
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}
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static __always_inline
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void shift_mac_4bytes_16bit(void *data)
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{
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__u16 *p = data;
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p[7] = p[5]; /* delete p[7] was vlan_hdr->h_vlan_TCI */
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p[6] = p[4]; /* delete p[6] was ethhdr->h_proto */
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p[5] = p[3];
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p[4] = p[2];
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p[3] = p[1];
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p[2] = p[0];
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}
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static __always_inline
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void shift_mac_4bytes_32bit(void *data)
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{
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__u32 *p = data;
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/* Assuming VLAN hdr present. The 4 bytes in p[3] that gets
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* overwritten, is ethhdr->h_proto and vlan_hdr->h_vlan_TCI.
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* The vlan_hdr->h_vlan_encapsulated_proto take over role as
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* ethhdr->h_proto.
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*/
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p[3] = p[2];
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p[2] = p[1];
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p[1] = p[0];
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}
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SEC("xdp_vlan_remove_outer2")
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int xdp_prognum3(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct ethhdr *orig_eth = data;
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struct parse_pkt pkt = { 0 };
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if (!parse_eth_frame(orig_eth, data_end, &pkt))
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return XDP_ABORTED;
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/* Skip packet if no outer VLAN was detected */
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if (pkt.vlan_outer_offset == 0)
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return XDP_PASS;
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/* Simply shift down MAC addrs 4 bytes, overwrite h_proto + TCI */
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shift_mac_4bytes_32bit(data);
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/* Move start of packet header seen by Linux kernel stack */
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bpf_xdp_adjust_head(ctx, VLAN_HDR_SZ);
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return XDP_PASS;
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}
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/*=====================================
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* BELOW: TC-hook based ebpf programs
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* ====================================
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* The TC-clsact eBPF programs (currently) need to be attach via TC commands
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*/
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SEC("tc_vlan_push")
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int _tc_progA(struct __sk_buff *ctx)
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{
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bpf_skb_vlan_push(ctx, bpf_htons(ETH_P_8021Q), TESTVLAN);
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return TC_ACT_OK;
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}
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/*
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Commands to setup TC to use above bpf prog:
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export ROOTDEV=ixgbe2
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export FILE=xdp_vlan01_kern.o
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# Re-attach clsact to clear/flush existing role
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tc qdisc del dev $ROOTDEV clsact 2> /dev/null ;\
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tc qdisc add dev $ROOTDEV clsact
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# Attach BPF prog EGRESS
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tc filter add dev $ROOTDEV egress \
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prio 1 handle 1 bpf da obj $FILE sec tc_vlan_push
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tc filter show dev $ROOTDEV egress
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*/
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