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-rw-r--r--net/core/ptp_classifier.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/net/core/ptp_classifier.c b/net/core/ptp_classifier.c
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+++ b/net/core/ptp_classifier.c
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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);
+
+bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type)
+{
+ struct ptp_header *hdr;
+
+ hdr = ptp_parse_header(skb, type);
+ if (!hdr)
+ return false;
+
+ return ptp_get_msgtype(hdr, type) == PTP_MSGTYPE_SYNC;
+}
+EXPORT_SYMBOL_GPL(ptp_msg_is_sync);
+
+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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