diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2017-06-11 00:50:47 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-06-10 19:05:47 -0400 |
| commit | ded092cd73c2c56a394b936f86897f29b2e131c0 (patch) | |
| tree | d8fc58484a521feb4eeb19bbb332e00148efe51e | |
| parent | 966789fb8636a35c3263076fea382263c5e56802 (diff) | |
bpf: add bpf_set_hash helper for tc progs
Allow for tc BPF programs to set a skb->hash, apart from clearing
and triggering a recalc that we have right now. It allows for BPF
to implement a custom hashing routine for skb_get_hash().
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/uapi/linux/bpf.h | 8 | ||||
| -rw-r--r-- | net/core/filter.c | 20 | ||||
| -rw-r--r-- | tools/include/uapi/linux/bpf.h | 8 |
3 files changed, 34 insertions, 2 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 9b2c10b45733..f94b48b168dc 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -513,6 +513,11 @@ union bpf_attr { * Get the owner uid of the socket stored inside sk_buff. * @skb: pointer to skb * Return: uid of the socket owner on success or overflowuid if failed. + * + * u32 bpf_set_hash(skb, hash) + * Set full skb->hash. + * @skb: pointer to skb + * @hash: hash to set */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -562,7 +567,8 @@ union bpf_attr { FN(xdp_adjust_head), \ FN(probe_read_str), \ FN(get_socket_cookie), \ - FN(get_socket_uid), + FN(get_socket_uid), \ + FN(set_hash), /* 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 4867391126e4..a65a3b25e104 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1874,6 +1874,24 @@ static const struct bpf_func_proto bpf_set_hash_invalid_proto = { .arg1_type = ARG_PTR_TO_CTX, }; +BPF_CALL_2(bpf_set_hash, struct sk_buff *, skb, u32, hash) +{ + /* Set user specified hash as L4(+), so that it gets returned + * on skb_get_hash() call unless BPF prog later on triggers a + * skb_clear_hash(). + */ + __skb_set_sw_hash(skb, hash, true); + return 0; +} + +static const struct bpf_func_proto bpf_set_hash_proto = { + .func = bpf_set_hash, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, +}; + BPF_CALL_3(bpf_skb_vlan_push, struct sk_buff *, skb, __be16, vlan_proto, u16, vlan_tci) { @@ -2744,6 +2762,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) return &bpf_get_hash_recalc_proto; case BPF_FUNC_set_hash_invalid: return &bpf_set_hash_invalid_proto; + case BPF_FUNC_set_hash: + return &bpf_set_hash_proto; case BPF_FUNC_perf_event_output: return &bpf_skb_event_output_proto; case BPF_FUNC_get_smp_processor_id: diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 9b2c10b45733..f94b48b168dc 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -513,6 +513,11 @@ union bpf_attr { * Get the owner uid of the socket stored inside sk_buff. * @skb: pointer to skb * Return: uid of the socket owner on success or overflowuid if failed. + * + * u32 bpf_set_hash(skb, hash) + * Set full skb->hash. + * @skb: pointer to skb + * @hash: hash to set */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -562,7 +567,8 @@ union bpf_attr { FN(xdp_adjust_head), \ FN(probe_read_str), \ FN(get_socket_cookie), \ - FN(get_socket_uid), + FN(get_socket_uid), \ + FN(set_hash), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call |