From 91b8270f2a4d1d9b268de90451cdca63a70052d6 Mon Sep 17 00:00:00 2001 From: Chenbo Feng Date: Wed, 22 Mar 2017 17:27:34 -0700 Subject: [PATCH] Add a helper function to get socket cookie in eBPF Retrieve the socket cookie generated by sock_gen_cookie() from a sk_buff with a known socket. Generates a new cookie if one was not yet set.If the socket pointer inside sk_buff is NULL, 0 is returned. The helper function coud be useful in monitoring per socket networking traffic statistics and provide a unique socket identifier per namespace. Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: Willem de Bruijn Signed-off-by: Chenbo Feng Signed-off-by: David S. Miller --- include/linux/sock_diag.h | 1 + include/uapi/linux/bpf.h | 9 ++++++++- net/core/filter.c | 17 +++++++++++++++++ net/core/sock_diag.c | 2 +- tools/include/uapi/linux/bpf.h | 3 ++- 5 files changed, 29 insertions(+), 3 deletions(-) diff --git a/include/linux/sock_diag.h b/include/linux/sock_diag.h index a0596ca0e80a..a2f8109bb215 100644 --- a/include/linux/sock_diag.h +++ b/include/linux/sock_diag.h @@ -24,6 +24,7 @@ void sock_diag_unregister(const struct sock_diag_handler *h); void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh)); void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh)); +u64 sock_gen_cookie(struct sock *sk); int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie); void sock_diag_save_cookie(struct sock *sk, __u32 *cookie); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ce6f029ac368..cdfc5595fbc1 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -459,6 +459,12 @@ union bpf_attr { * Return: * > 0 length of the string including the trailing NUL on success * < 0 error + * + * u64 bpf_bpf_get_socket_cookie(skb) + * Get the cookie for the socket stored inside sk_buff. + * @skb: pointer to skb + * Return: 8 Bytes non-decreasing number on success or 0 if the socket + * field is missing inside sk_buff */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -506,7 +512,8 @@ union bpf_attr { FN(get_numa_node_id), \ FN(skb_change_head), \ FN(xdp_adjust_head), \ - FN(probe_read_str), + FN(probe_read_str), \ + FN(get_socket_cookie), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/net/core/filter.c b/net/core/filter.c index c7f0ccd1c0d3..35b0f97c3fdf 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -2606,6 +2607,18 @@ static const struct bpf_func_proto bpf_xdp_event_output_proto = { .arg5_type = ARG_CONST_SIZE, }; +BPF_CALL_1(bpf_get_socket_cookie, struct sk_buff *, skb) +{ + return skb->sk ? sock_gen_cookie(skb->sk) : 0; +} + +static const struct bpf_func_proto bpf_get_socket_cookie_proto = { + .func = bpf_get_socket_cookie, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + static const struct bpf_func_proto * bpf_base_func_proto(enum bpf_func_id func_id) { @@ -2640,6 +2653,8 @@ sk_filter_func_proto(enum bpf_func_id func_id) switch (func_id) { case BPF_FUNC_skb_load_bytes: return &bpf_skb_load_bytes_proto; + case BPF_FUNC_get_socket_cookie: + return &bpf_get_socket_cookie_proto; default: return bpf_base_func_proto(func_id); } @@ -2699,6 +2714,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) return &bpf_get_smp_processor_id_proto; case BPF_FUNC_skb_under_cgroup: return &bpf_skb_under_cgroup_proto; + case BPF_FUNC_get_socket_cookie: + return &bpf_get_socket_cookie_proto; default: return bpf_base_func_proto(func_id); } diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c index 8d11ee75a100..fb9d0e2fd148 100644 --- a/net/core/sock_diag.c +++ b/net/core/sock_diag.c @@ -19,7 +19,7 @@ static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh); static DEFINE_MUTEX(sock_diag_table_mutex); static struct workqueue_struct *broadcast_wq; -static u64 sock_gen_cookie(struct sock *sk) +u64 sock_gen_cookie(struct sock *sk) { while (1) { u64 res = atomic64_read(&sk->sk_cookie); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index ce6f029ac368..a3851859e5f3 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -506,7 +506,8 @@ union bpf_attr { FN(get_numa_node_id), \ FN(skb_change_head), \ FN(xdp_adjust_head), \ - FN(probe_read_str), + FN(probe_read_str), \ + FN(get_socket_cookie), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call -- 2.20.1