From c19844c780bc417a7a47497eba7ee07f8ea8d7f8 Mon Sep 17 00:00:00 2001 From: Zvi Effron Date: Wed, 7 Jul 2021 22:16:55 +0000 Subject: [PATCH] bpf: Support input xdp_md context in BPF_PROG_TEST_RUN Support passing a xdp_md via ctx_in/ctx_out in bpf_attr for BPF_PROG_TEST_RUN. The intended use case is to pass some XDP meta data to the test runs of XDP programs that are used as tail calls. For programs that use bpf_prog_test_run_xdp, support xdp_md input and output. Unlike with an actual xdp_md during a non-test run, data_meta must be 0 because it must point to the start of the provided user data. From the initial xdp_md, use data and data_end to adjust the pointers in the generated xdp_buff. All other non-zero fields are prohibited (with EINVAL). If the user has set ctx_out/ctx_size_out, copy the (potentially different) xdp_md back to the userspace. We require all fields of input xdp_md except the ones we explicitly support to be set to zero. The expectation is that in the future we might add support for more fields and we want to fail explicitly if the user runs the program on the kernel where we don't yet support them. Co-developed-by: Cody Haas Co-developed-by: Lisa Watanabe Signed-off-by: Cody Haas Signed-off-by: Lisa Watanabe Signed-off-by: Zvi Effron Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210707221657.3985075-3-zeffron@riotgames.com --- include/uapi/linux/bpf.h | 3 -- net/bpf/test_run.c | 67 +++++++++++++++++++++++++++++++++++----- 2 files changed, 59 insertions(+), 11 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index bf9252c7381e8..b46a383e8db7f 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -324,9 +324,6 @@ union bpf_iter_link_info { * **BPF_PROG_TYPE_SK_LOOKUP** * *data_in* and *data_out* must be NULL. * - * **BPF_PROG_TYPE_XDP** - * *ctx_in* and *ctx_out* must be NULL. - * * **BPF_PROG_TYPE_RAW_TRACEPOINT**, * **BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE** * diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index aa47af349ba80..229c5deb813c5 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -15,6 +15,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -687,6 +688,22 @@ out: return ret; } +static int xdp_convert_md_to_buff(struct xdp_md *xdp_md, struct xdp_buff *xdp) +{ + if (!xdp_md) + return 0; + + if (xdp_md->egress_ifindex != 0) + return -EINVAL; + + if (xdp_md->ingress_ifindex != 0 || xdp_md->rx_queue_index != 0) + return -EINVAL; + + xdp->data = xdp->data_meta + xdp_md->data; + + return 0; +} + int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr) { @@ -697,35 +714,69 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, struct netdev_rx_queue *rxqueue; struct xdp_buff xdp = {}; u32 retval, duration; + struct xdp_md *ctx; u32 max_data_sz; void *data; - int ret; + int ret = -EINVAL; - if (kattr->test.ctx_in || kattr->test.ctx_out) - return -EINVAL; + ctx = bpf_ctx_init(kattr, sizeof(struct xdp_md)); + if (IS_ERR(ctx)) + return PTR_ERR(ctx); + + if (ctx) { + /* There can't be user provided data before the meta data */ + if (ctx->data_meta || ctx->data_end != size || + ctx->data > ctx->data_end || + unlikely(xdp_metalen_invalid(ctx->data))) + goto free_ctx; + /* Meta data is allocated from the headroom */ + headroom -= ctx->data; + } /* XDP have extra tailroom as (most) drivers use full page */ max_data_sz = 4096 - headroom - tailroom; data = bpf_test_init(kattr, max_data_sz, headroom, tailroom); - if (IS_ERR(data)) - return PTR_ERR(data); + if (IS_ERR(data)) { + ret = PTR_ERR(data); + goto free_ctx; + } rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0); xdp_init_buff(&xdp, headroom + max_data_sz + tailroom, &rxqueue->xdp_rxq); xdp_prepare_buff(&xdp, data, headroom, size, true); + ret = xdp_convert_md_to_buff(ctx, &xdp); + if (ret) + goto free_data; + bpf_prog_change_xdp(NULL, prog); ret = bpf_test_run(prog, &xdp, repeat, &retval, &duration, true); if (ret) goto out; - if (xdp.data != data + headroom || xdp.data_end != xdp.data + size) - size = xdp.data_end - xdp.data; - ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration); + + if (xdp.data_meta != data + headroom || + xdp.data_end != xdp.data_meta + size) + size = xdp.data_end - xdp.data_meta; + + if (ctx) { + ctx->data = xdp.data - xdp.data_meta; + ctx->data_end = xdp.data_end - xdp.data_meta; + } + + ret = bpf_test_finish(kattr, uattr, xdp.data_meta, size, retval, + duration); + if (!ret) + ret = bpf_ctx_finish(kattr, uattr, ctx, + sizeof(struct xdp_md)); + out: bpf_prog_change_xdp(prog, NULL); +free_data: kfree(data); +free_ctx: + kfree(ctx); return ret; } -- 2.39.5