[PATCH v5 bpf-next 04/11] net: Add BPF_XDP_EGRESS as a bpf_attach_type
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STALE2356d
From: David Ahern <dsahern@kernel.org>
Date: 2020-05-13 01:46:18
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Revision v5 (5 revisions archived).
Revisions (5)
From: David Ahern <redacted> Add new bpf_attach_type, BPF_XDP_EGRESS, for BPF programs attached at the XDP layer, but the egress path. Since egress path will not have ingress_ifindex and rx_queue_index set, update xdp_is_valid_access to block access to these entries in the xdp context when a program is attached with expected_attach_type set. Update dev_change_xdp_fd to verify expected_attach_type for a program is BPF_XDP_EGRESS if egress argument is set. The next patch adds support for the egress ifindex. Signed-off-by: Prashant Bhole <redacted> Co-developed-by: David Ahern <redacted> Signed-off-by: David Ahern <redacted> --- include/uapi/linux/bpf.h | 1 + net/core/dev.c | 11 +++++++++++ net/core/filter.c | 11 +++++++++++ tools/include/uapi/linux/bpf.h | 1 + 4 files changed, 24 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index bfb31c1be219..05accb95bb4a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -220,6 +220,7 @@ enum bpf_attach_type { BPF_MODIFY_RETURN, BPF_LSM_MAC, BPF_TRACE_ITER, + BPF_XDP_EGRESS, __MAX_BPF_ATTACH_TYPE };
diff --git a/net/core/dev.c b/net/core/dev.c
index c0455e764f97..88672ea4fc80 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -8737,6 +8737,17 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, if (IS_ERR(prog)) return PTR_ERR(prog); + if (egress && prog->expected_attach_type != BPF_XDP_EGRESS) { + NL_SET_ERR_MSG(extack, "XDP program in Tx path must use BPF_XDP_EGRESS attach type"); + bpf_prog_put(prog); + return -EINVAL; + } + if (!egress && prog->expected_attach_type == BPF_XDP_EGRESS) { + NL_SET_ERR_MSG(extack, "XDP program in Rx path can not use BPF_XDP_EGRESS attach type"); + bpf_prog_put(prog); + return -EINVAL; + } + if (!offload && bpf_prog_is_dev_bound(prog->aux)) { NL_SET_ERR_MSG(extack, "using device-bound program without HW_MODE flag is not supported"); bpf_prog_put(prog);
diff --git a/net/core/filter.c b/net/core/filter.c
index da0634979f53..19272eb7bb8f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -6931,6 +6931,17 @@ static bool xdp_is_valid_access(int off, int size, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { + /* Rx data is only accessible from original XDP where + * expected_attach_type is not set + */ + if (prog->expected_attach_type) { + switch (off) { + case offsetof(struct xdp_md, ingress_ifindex): + case offsetof(struct xdp_md, rx_queue_index): + return false; + } + } + if (type == BPF_WRITE) { if (bpf_prog_is_dev_bound(prog->aux)) { switch (off) {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index bfb31c1be219..05accb95bb4a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h@@ -220,6 +220,7 @@ enum bpf_attach_type { BPF_MODIFY_RETURN, BPF_LSM_MAC, BPF_TRACE_ITER, + BPF_XDP_EGRESS, __MAX_BPF_ATTACH_TYPE };
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2.21.1 (Apple Git-122.3)