On 11/10/2017 08:17 PM, Vlad Dumitrescu wrote:
From: Vlad Dumitrescu <vla...@google.com>Allows BPF_PROG_TYPE_SOCK_OPS programs to read sk_priority. Signed-off-by: Vlad Dumitrescu <vla...@google.com> --- include/uapi/linux/bpf.h | 1 + net/core/filter.c | 11 +++++++++++ tools/include/uapi/linux/bpf.h | 1 + 3 files changed, 13 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index e880ae6434ee..9757a2002513 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -947,6 +947,7 @@ struct bpf_sock_ops { __u32 local_ip6[4]; /* Stored in network byte order */ __u32 remote_port; /* Stored in network byte order */ __u32 local_port; /* stored in host byte order */ + __u32 priority; };/* List of known BPF sock_ops operators.diff --git a/net/core/filter.c b/net/core/filter.c index 61c791f9f628..a6329642d047 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4449,6 +4449,17 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, *insn++ = BPF_LDX_MEM(BPF_H, si->dst_reg, si->dst_reg, offsetof(struct sock_common, skc_num)); break; + + case offsetof(struct bpf_sock_ops, priority): + BUILD_BUG_ON(FIELD_SIZEOF(struct sock, sk_priority) != 4); + + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( + struct bpf_sock_ops_kern, sk), + si->dst_reg, si->src_reg, + offsetof(struct bpf_sock_ops_kern, sk)); + *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg, + offsetof(struct sock, sk_priority)); + break;
Hm, I don't think this would work, I actually think your initial patch was ok. bpf_setsockopt() as well as bpf_getsockopt() check for sk_fullsock(sk) right before accessing options on either socket or TCP level, and bail out with error otherwise; in such cases we'd read something else here and assume it's sk_priority.
} return insn - insn_buf; } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index e880ae6434ee..9757a2002513 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -947,6 +947,7 @@ struct bpf_sock_ops { __u32 local_ip6[4]; /* Stored in network byte order */ __u32 remote_port; /* Stored in network byte order */ __u32 local_port; /* stored in host byte order */ + __u32 priority; };/* List of known BPF sock_ops operators.
