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linux/net/core/ptp_classifier.c
Andrii Nakryiko fb7dd8bca0 bpf: Refactor BPF_PROG_RUN into a function 
Turn BPF_PROG_RUN into a proper always inlined function. No functional and
performance changes are intended, but it makes it much easier to understand
what's going on with how BPF programs are actually get executed. It's more
obvious what types and callbacks are expected. Also extra () around input
parameters can be dropped, as well as `__` variable prefixes intended to avoid
naming collisions, which makes the code simpler to read and write.

This refactoring also highlighted one extra issue. BPF_PROG_RUN is both
a macro and an enum value (BPF_PROG_RUN == BPF_PROG_TEST_RUN). Turning
BPF_PROG_RUN into a function causes naming conflict compilation error. So
rename BPF_PROG_RUN into lower-case bpf_prog_run(), similar to
bpf_prog_run_xdp(), bpf_prog_run_pin_on_cpu(), etc. All existing callers of
BPF_PROG_RUN, the macro, are switched to bpf_prog_run() explicitly.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210815070609.987780-2-andrii@kernel.org
2021-08-17 00:45:07 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/* PTP classifier
*/
/* The below program is the bpf_asm (tools/net/) representation of
* the opcode array in the ptp_filter structure.
*
* For convenience, this can easily be altered and reviewed with
* bpf_asm and bpf_dbg, e.g. `./bpf_asm -c prog` where prog is a
* simple file containing the below program:
*
* ldh [12] ; load ethertype
*
* ; PTP over UDP over IPv4 over Ethernet
* test_ipv4:
* jneq #0x800, test_ipv6 ; ETH_P_IP ?
* ldb [23] ; load proto
* jneq #17, drop_ipv4 ; IPPROTO_UDP ?
* ldh [20] ; load frag offset field
* jset #0x1fff, drop_ipv4 ; don't allow fragments
* ldxb 4*([14]&0xf) ; load IP header len
* ldh [x + 16] ; load UDP dst port
* jneq #319, drop_ipv4 ; is port PTP_EV_PORT ?
* ldh [x + 22] ; load payload
* and #0xf ; mask PTP_CLASS_VMASK
* or #0x10 ; PTP_CLASS_IPV4
* ret a ; return PTP class
* drop_ipv4: ret #0x0 ; PTP_CLASS_NONE
*
* ; PTP over UDP over IPv6 over Ethernet
* test_ipv6:
* jneq #0x86dd, test_8021q ; ETH_P_IPV6 ?
* ldb [20] ; load proto
* jneq #17, drop_ipv6 ; IPPROTO_UDP ?
* ldh [56] ; load UDP dst port
* jneq #319, drop_ipv6 ; is port PTP_EV_PORT ?
* ldh [62] ; load payload
* and #0xf ; mask PTP_CLASS_VMASK
* or #0x20 ; PTP_CLASS_IPV6
* ret a ; return PTP class
* drop_ipv6: ret #0x0 ; PTP_CLASS_NONE
*
* ; PTP over 802.1Q over Ethernet
* test_8021q:
* jneq #0x8100, test_ieee1588 ; ETH_P_8021Q ?
* ldh [16] ; load inner type
* jneq #0x88f7, test_8021q_ipv4 ; ETH_P_1588 ?
* ldb [18] ; load payload
* and #0x8 ; as we don't have ports here, test
* jneq #0x0, drop_ieee1588 ; for PTP_GEN_BIT and drop these
* ldh [18] ; reload payload
* and #0xf ; mask PTP_CLASS_VMASK
* or #0xc0 ; PTP_CLASS_VLAN|PTP_CLASS_L2
* ret a ; return PTP class
*
* ; PTP over UDP over IPv4 over 802.1Q over Ethernet
* test_8021q_ipv4:
* jneq #0x800, test_8021q_ipv6 ; ETH_P_IP ?
* ldb [27] ; load proto
* jneq #17, drop_8021q_ipv4 ; IPPROTO_UDP ?
* ldh [24] ; load frag offset field
* jset #0x1fff, drop_8021q_ipv4; don't allow fragments
* ldxb 4*([18]&0xf) ; load IP header len
* ldh [x + 20] ; load UDP dst port
* jneq #319, drop_8021q_ipv4 ; is port PTP_EV_PORT ?
* ldh [x + 26] ; load payload
* and #0xf ; mask PTP_CLASS_VMASK
* or #0x90 ; PTP_CLASS_VLAN|PTP_CLASS_IPV4
* ret a ; return PTP class
* drop_8021q_ipv4: ret #0x0 ; PTP_CLASS_NONE
*
* ; PTP over UDP over IPv6 over 802.1Q over Ethernet
* test_8021q_ipv6:
* jneq #0x86dd, drop_8021q_ipv6 ; ETH_P_IPV6 ?
* ldb [24] ; load proto
* jneq #17, drop_8021q_ipv6 ; IPPROTO_UDP ?
* ldh [60] ; load UDP dst port
* jneq #319, drop_8021q_ipv6 ; is port PTP_EV_PORT ?
* ldh [66] ; load payload
* and #0xf ; mask PTP_CLASS_VMASK
* or #0xa0 ; PTP_CLASS_VLAN|PTP_CLASS_IPV6
* ret a ; return PTP class
* drop_8021q_ipv6: ret #0x0 ; PTP_CLASS_NONE
*
* ; PTP over Ethernet
* test_ieee1588:
* jneq #0x88f7, drop_ieee1588 ; ETH_P_1588 ?
* ldb [14] ; load payload
* and #0x8 ; as we don't have ports here, test
* jneq #0x0, drop_ieee1588 ; for PTP_GEN_BIT and drop these
* ldh [14] ; reload payload
* and #0xf ; mask PTP_CLASS_VMASK
* or #0x40 ; PTP_CLASS_L2
* ret a ; return PTP class
* drop_ieee1588: ret #0x0 ; PTP_CLASS_NONE
*/
#include <linux/skbuff.h>
#include <linux/filter.h>
#include <linux/ptp_classify.h>
static struct bpf_prog *ptp_insns __read_mostly;
unsigned int ptp_classify_raw(const struct sk_buff *skb)
{
return bpf_prog_run(ptp_insns, skb);
}
EXPORT_SYMBOL_GPL(ptp_classify_raw);
struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type)
{
u8 *ptr = skb_mac_header(skb);
if (type & PTP_CLASS_VLAN)
ptr += VLAN_HLEN;
switch (type & PTP_CLASS_PMASK) {
case PTP_CLASS_IPV4:
ptr += IPV4_HLEN(ptr) + UDP_HLEN;
break;
case PTP_CLASS_IPV6:
ptr += IP6_HLEN + UDP_HLEN;
break;
case PTP_CLASS_L2:
break;
default:
return NULL;
}
ptr += ETH_HLEN;
/* Ensure that the entire header is present in this packet. */
if (ptr + sizeof(struct ptp_header) > skb->data + skb->len)
return NULL;
return (struct ptp_header *)ptr;
}
EXPORT_SYMBOL_GPL(ptp_parse_header);
void __init ptp_classifier_init(void)
{
static struct sock_filter ptp_filter[] __initdata = {
{ 0x28, 0, 0, 0x0000000c },
{ 0x15, 0, 12, 0x00000800 },
{ 0x30, 0, 0, 0x00000017 },
{ 0x15, 0, 9, 0x00000011 },
{ 0x28, 0, 0, 0x00000014 },
{ 0x45, 7, 0, 0x00001fff },
{ 0xb1, 0, 0, 0x0000000e },
{ 0x48, 0, 0, 0x00000010 },
{ 0x15, 0, 4, 0x0000013f },
{ 0x48, 0, 0, 0x00000016 },
{ 0x54, 0, 0, 0x0000000f },
{ 0x44, 0, 0, 0x00000010 },
{ 0x16, 0, 0, 0x00000000 },
{ 0x06, 0, 0, 0x00000000 },
{ 0x15, 0, 9, 0x000086dd },
{ 0x30, 0, 0, 0x00000014 },
{ 0x15, 0, 6, 0x00000011 },
{ 0x28, 0, 0, 0x00000038 },
{ 0x15, 0, 4, 0x0000013f },
{ 0x28, 0, 0, 0x0000003e },
{ 0x54, 0, 0, 0x0000000f },
{ 0x44, 0, 0, 0x00000020 },
{ 0x16, 0, 0, 0x00000000 },
{ 0x06, 0, 0, 0x00000000 },
{ 0x15, 0, 32, 0x00008100 },
{ 0x28, 0, 0, 0x00000010 },
{ 0x15, 0, 7, 0x000088f7 },
{ 0x30, 0, 0, 0x00000012 },
{ 0x54, 0, 0, 0x00000008 },
{ 0x15, 0, 35, 0x00000000 },
{ 0x28, 0, 0, 0x00000012 },
{ 0x54, 0, 0, 0x0000000f },
{ 0x44, 0, 0, 0x000000c0 },
{ 0x16, 0, 0, 0x00000000 },
{ 0x15, 0, 12, 0x00000800 },
{ 0x30, 0, 0, 0x0000001b },
{ 0x15, 0, 9, 0x00000011 },
{ 0x28, 0, 0, 0x00000018 },
{ 0x45, 7, 0, 0x00001fff },
{ 0xb1, 0, 0, 0x00000012 },
{ 0x48, 0, 0, 0x00000014 },
{ 0x15, 0, 4, 0x0000013f },
{ 0x48, 0, 0, 0x0000001a },
{ 0x54, 0, 0, 0x0000000f },
{ 0x44, 0, 0, 0x00000090 },
{ 0x16, 0, 0, 0x00000000 },
{ 0x06, 0, 0, 0x00000000 },
{ 0x15, 0, 8, 0x000086dd },
{ 0x30, 0, 0, 0x00000018 },
{ 0x15, 0, 6, 0x00000011 },
{ 0x28, 0, 0, 0x0000003c },
{ 0x15, 0, 4, 0x0000013f },
{ 0x28, 0, 0, 0x00000042 },
{ 0x54, 0, 0, 0x0000000f },
{ 0x44, 0, 0, 0x000000a0 },
{ 0x16, 0, 0, 0x00000000 },
{ 0x06, 0, 0, 0x00000000 },
{ 0x15, 0, 7, 0x000088f7 },
{ 0x30, 0, 0, 0x0000000e },
{ 0x54, 0, 0, 0x00000008 },
{ 0x15, 0, 4, 0x00000000 },
{ 0x28, 0, 0, 0x0000000e },
{ 0x54, 0, 0, 0x0000000f },
{ 0x44, 0, 0, 0x00000040 },
{ 0x16, 0, 0, 0x00000000 },
{ 0x06, 0, 0, 0x00000000 },
};
struct sock_fprog_kern ptp_prog;
ptp_prog.len = ARRAY_SIZE(ptp_filter);
ptp_prog.filter = ptp_filter;
BUG_ON(bpf_prog_create(&ptp_insns, &ptp_prog));
}
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