bpf: Add struct bpf_tcp_sock and BPF_FUNC_tcp_sock
This patch adds a helper function BPF_FUNC_tcp_sock and it
is currently available for cg_skb and sched_(cls|act):
struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk);
int cg_skb_foo(struct __sk_buff *skb) {
struct bpf_tcp_sock *tp;
struct bpf_sock *sk;
__u32 snd_cwnd;
sk = skb->sk;
if (!sk)
return 1;
tp = bpf_tcp_sock(sk);
if (!tp)
return 1;
snd_cwnd = tp->snd_cwnd;
/* ... */
return 1;
}
A 'struct bpf_tcp_sock' is also added to the uapi bpf.h to provide
read-only access. bpf_tcp_sock has all the existing tcp_sock's fields
that has already been exposed by the bpf_sock_ops.
i.e. no new tcp_sock's fields are exposed in bpf.h.
This helper returns a pointer to the tcp_sock. If it is not a tcp_sock
or it cannot be traced back to a tcp_sock by sk_to_full_sk(), it
returns NULL. Hence, the caller needs to check for NULL before
accessing it.
The current use case is to expose members from tcp_sock
to allow a cg_skb_bpf_prog to provide per cgroup traffic
policing/shaping.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
hifive-unleashed-5.1
Martin KaFai Lau
Alexei Starovoitov
parent
9b1f3d6e5a
commit
655a51e536
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@ -204,6 +204,7 @@ enum bpf_return_type {
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RET_PTR_TO_MAP_VALUE, /* returns a pointer to map elem value */
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RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */
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RET_PTR_TO_SOCKET_OR_NULL, /* returns a pointer to a socket or NULL */
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RET_PTR_TO_TCP_SOCK_OR_NULL, /* returns a pointer to a tcp_sock or NULL */
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};
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/* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
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@ -259,6 +260,8 @@ enum bpf_reg_type {
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PTR_TO_SOCKET_OR_NULL, /* reg points to struct bpf_sock or NULL */
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PTR_TO_SOCK_COMMON, /* reg points to sock_common */
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PTR_TO_SOCK_COMMON_OR_NULL, /* reg points to sock_common or NULL */
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PTR_TO_TCP_SOCK, /* reg points to struct tcp_sock */
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PTR_TO_TCP_SOCK_OR_NULL, /* reg points to struct tcp_sock or NULL */
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};
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/* The information passed from prog-specific *_is_valid_access
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@ -956,4 +959,31 @@ static inline u32 bpf_sock_convert_ctx_access(enum bpf_access_type type,
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}
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#endif
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#ifdef CONFIG_INET
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bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
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struct bpf_insn_access_aux *info);
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u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type type,
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const struct bpf_insn *si,
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struct bpf_insn *insn_buf,
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struct bpf_prog *prog,
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u32 *target_size);
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#else
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static inline bool bpf_tcp_sock_is_valid_access(int off, int size,
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enum bpf_access_type type,
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struct bpf_insn_access_aux *info)
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{
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return false;
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}
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static inline u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type type,
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const struct bpf_insn *si,
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struct bpf_insn *insn_buf,
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struct bpf_prog *prog,
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u32 *target_size)
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{
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return 0;
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}
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#endif /* CONFIG_INET */
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#endif /* _LINUX_BPF_H */
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@ -2337,6 +2337,15 @@ union bpf_attr {
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* Return
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* A **struct bpf_sock** pointer on success, or NULL in
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* case of failure.
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*
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* struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
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* Description
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* This helper gets a **struct bpf_tcp_sock** pointer from a
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* **struct bpf_sock** pointer.
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*
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* Return
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* A **struct bpf_tcp_sock** pointer on success, or NULL in
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* case of failure.
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*/
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#define __BPF_FUNC_MAPPER(FN) \
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FN(unspec), \
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@ -2434,7 +2443,8 @@ union bpf_attr {
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FN(rc_pointer_rel), \
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FN(spin_lock), \
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FN(spin_unlock), \
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FN(sk_fullsock),
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FN(sk_fullsock), \
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FN(tcp_sock),
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/* integer value in 'imm' field of BPF_CALL instruction selects which helper
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* function eBPF program intends to call
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@ -2616,6 +2626,45 @@ struct bpf_sock {
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__u32 state;
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};
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struct bpf_tcp_sock {
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__u32 snd_cwnd; /* Sending congestion window */
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__u32 srtt_us; /* smoothed round trip time << 3 in usecs */
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__u32 rtt_min;
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__u32 snd_ssthresh; /* Slow start size threshold */
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__u32 rcv_nxt; /* What we want to receive next */
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__u32 snd_nxt; /* Next sequence we send */
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__u32 snd_una; /* First byte we want an ack for */
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__u32 mss_cache; /* Cached effective mss, not including SACKS */
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__u32 ecn_flags; /* ECN status bits. */
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__u32 rate_delivered; /* saved rate sample: packets delivered */
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__u32 rate_interval_us; /* saved rate sample: time elapsed */
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__u32 packets_out; /* Packets which are "in flight" */
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__u32 retrans_out; /* Retransmitted packets out */
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__u32 total_retrans; /* Total retransmits for entire connection */
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__u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
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* total number of segments in.
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*/
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__u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
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* total number of data segments in.
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*/
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__u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
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* The total number of segments sent.
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*/
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__u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
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* total number of data segments sent.
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*/
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__u32 lost_out; /* Lost packets */
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__u32 sacked_out; /* SACK'd packets */
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__u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
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* sum(delta(rcv_nxt)), or how many bytes
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* were acked.
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*/
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__u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
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* sum(delta(snd_una)), or how many bytes
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* were acked.
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*/
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};
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struct bpf_sock_tuple {
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union {
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struct {
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@ -334,14 +334,16 @@ static bool type_is_pkt_pointer(enum bpf_reg_type type)
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static bool type_is_sk_pointer(enum bpf_reg_type type)
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{
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return type == PTR_TO_SOCKET ||
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type == PTR_TO_SOCK_COMMON;
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type == PTR_TO_SOCK_COMMON ||
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type == PTR_TO_TCP_SOCK;
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}
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static bool reg_type_may_be_null(enum bpf_reg_type type)
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{
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return type == PTR_TO_MAP_VALUE_OR_NULL ||
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type == PTR_TO_SOCKET_OR_NULL ||
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type == PTR_TO_SOCK_COMMON_OR_NULL;
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type == PTR_TO_SOCK_COMMON_OR_NULL ||
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type == PTR_TO_TCP_SOCK_OR_NULL;
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}
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static bool type_is_refcounted(enum bpf_reg_type type)
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@ -407,6 +409,8 @@ static const char * const reg_type_str[] = {
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[PTR_TO_SOCKET_OR_NULL] = "sock_or_null",
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[PTR_TO_SOCK_COMMON] = "sock_common",
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[PTR_TO_SOCK_COMMON_OR_NULL] = "sock_common_or_null",
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[PTR_TO_TCP_SOCK] = "tcp_sock",
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[PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null",
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};
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static char slot_type_char[] = {
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@ -1209,6 +1213,8 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
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case PTR_TO_SOCKET_OR_NULL:
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case PTR_TO_SOCK_COMMON:
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case PTR_TO_SOCK_COMMON_OR_NULL:
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case PTR_TO_TCP_SOCK:
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case PTR_TO_TCP_SOCK_OR_NULL:
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return true;
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default:
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return false;
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@ -1662,6 +1668,9 @@ static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
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case PTR_TO_SOCKET:
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valid = bpf_sock_is_valid_access(off, size, t, &info);
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break;
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case PTR_TO_TCP_SOCK:
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valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
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break;
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default:
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valid = false;
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}
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@ -1823,6 +1832,9 @@ static int check_ptr_alignment(struct bpf_verifier_env *env,
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case PTR_TO_SOCK_COMMON:
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pointer_desc = "sock_common ";
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break;
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case PTR_TO_TCP_SOCK:
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pointer_desc = "tcp_sock ";
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break;
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default:
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break;
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}
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@ -3148,6 +3160,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
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/* For mark_ptr_or_null_reg() */
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regs[BPF_REG_0].id = ++env->id_gen;
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}
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} else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) {
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mark_reg_known_zero(env, regs, BPF_REG_0);
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regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL;
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regs[BPF_REG_0].id = ++env->id_gen;
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} else {
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verbose(env, "unknown return type %d of func %s#%d\n",
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fn->ret_type, func_id_name(func_id), func_id);
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@ -3409,6 +3425,8 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
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case PTR_TO_SOCKET_OR_NULL:
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case PTR_TO_SOCK_COMMON:
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case PTR_TO_SOCK_COMMON_OR_NULL:
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case PTR_TO_TCP_SOCK:
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case PTR_TO_TCP_SOCK_OR_NULL:
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verbose(env, "R%d pointer arithmetic on %s prohibited\n",
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dst, reg_type_str[ptr_reg->type]);
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return -EACCES;
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@ -4644,6 +4662,8 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
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reg->type = PTR_TO_SOCKET;
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} else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) {
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reg->type = PTR_TO_SOCK_COMMON;
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} else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {
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reg->type = PTR_TO_TCP_SOCK;
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}
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if (is_null || !(reg_is_refcounted(reg) ||
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reg_may_point_to_spin_lock(reg))) {
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@ -5839,6 +5859,8 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
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case PTR_TO_SOCKET_OR_NULL:
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case PTR_TO_SOCK_COMMON:
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case PTR_TO_SOCK_COMMON_OR_NULL:
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case PTR_TO_TCP_SOCK:
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case PTR_TO_TCP_SOCK_OR_NULL:
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/* Only valid matches are exact, which memcmp() above
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* would have accepted
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*/
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@ -6161,6 +6183,8 @@ static bool reg_type_mismatch_ok(enum bpf_reg_type type)
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case PTR_TO_SOCKET_OR_NULL:
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case PTR_TO_SOCK_COMMON:
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case PTR_TO_SOCK_COMMON_OR_NULL:
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case PTR_TO_TCP_SOCK:
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case PTR_TO_TCP_SOCK_OR_NULL:
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return false;
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default:
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return true;
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@ -7166,6 +7190,9 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
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case PTR_TO_SOCK_COMMON:
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convert_ctx_access = bpf_sock_convert_ctx_access;
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break;
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case PTR_TO_TCP_SOCK:
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convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
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break;
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default:
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continue;
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}
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@ -5315,6 +5315,79 @@ static const struct bpf_func_proto bpf_sock_addr_sk_lookup_udp_proto = {
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.arg5_type = ARG_ANYTHING,
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};
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bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
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struct bpf_insn_access_aux *info)
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{
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if (off < 0 || off >= offsetofend(struct bpf_tcp_sock, bytes_acked))
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return false;
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if (off % size != 0)
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return false;
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switch (off) {
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case offsetof(struct bpf_tcp_sock, bytes_received):
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case offsetof(struct bpf_tcp_sock, bytes_acked):
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return size == sizeof(__u64);
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default:
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return size == sizeof(__u32);
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}
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}
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u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type type,
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const struct bpf_insn *si,
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struct bpf_insn *insn_buf,
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struct bpf_prog *prog, u32 *target_size)
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{
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struct bpf_insn *insn = insn_buf;
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#define BPF_TCP_SOCK_GET_COMMON(FIELD) \
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do { \
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BUILD_BUG_ON(FIELD_SIZEOF(struct tcp_sock, FIELD) > \
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FIELD_SIZEOF(struct bpf_tcp_sock, FIELD)); \
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*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct tcp_sock, FIELD),\
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si->dst_reg, si->src_reg, \
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offsetof(struct tcp_sock, FIELD)); \
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} while (0)
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CONVERT_COMMON_TCP_SOCK_FIELDS(struct bpf_tcp_sock,
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BPF_TCP_SOCK_GET_COMMON);
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if (insn > insn_buf)
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return insn - insn_buf;
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switch (si->off) {
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case offsetof(struct bpf_tcp_sock, rtt_min):
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BUILD_BUG_ON(FIELD_SIZEOF(struct tcp_sock, rtt_min) !=
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sizeof(struct minmax));
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BUILD_BUG_ON(sizeof(struct minmax) <
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sizeof(struct minmax_sample));
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*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->src_reg,
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offsetof(struct tcp_sock, rtt_min) +
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offsetof(struct minmax_sample, v));
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break;
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}
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return insn - insn_buf;
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}
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BPF_CALL_1(bpf_tcp_sock, struct sock *, sk)
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{
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sk = sk_to_full_sk(sk);
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if (sk_fullsock(sk) && sk->sk_protocol == IPPROTO_TCP)
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return (unsigned long)sk;
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return (unsigned long)NULL;
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}
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static const struct bpf_func_proto bpf_tcp_sock_proto = {
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.func = bpf_tcp_sock,
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.gpl_only = false,
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.ret_type = RET_PTR_TO_TCP_SOCK_OR_NULL,
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.arg1_type = ARG_PTR_TO_SOCK_COMMON,
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};
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#endif /* CONFIG_INET */
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bool bpf_helper_changes_pkt_data(void *func)
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@ -5470,6 +5543,10 @@ cg_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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return &bpf_get_local_storage_proto;
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case BPF_FUNC_sk_fullsock:
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return &bpf_sk_fullsock_proto;
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#ifdef CONFIG_INET
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case BPF_FUNC_tcp_sock:
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return &bpf_tcp_sock_proto;
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#endif
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default:
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return sk_filter_func_proto(func_id, prog);
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}
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@ -5560,6 +5637,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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return &bpf_sk_lookup_udp_proto;
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case BPF_FUNC_sk_release:
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return &bpf_sk_release_proto;
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case BPF_FUNC_tcp_sock:
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return &bpf_tcp_sock_proto;
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#endif
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default:
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return bpf_base_func_proto(func_id);
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Loading…
Reference in New Issue