diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_check_mtu.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_check_mtu.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_check_mtu.c b/tools/testing/selftests/bpf/progs/test_check_mtu.c new file mode 100644 index 000000000000..2ec1de11a3ae --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_check_mtu.c @@ -0,0 +1,290 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Jesper Dangaard Brouer */ + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <linux/if_ether.h> + +#include <stddef.h> +#include <stdint.h> + +char _license[] SEC("license") = "GPL"; + +/* Userspace will update with MTU it can see on device */ +volatile const int GLOBAL_USER_MTU; +volatile const __u32 GLOBAL_USER_IFINDEX; + +/* BPF-prog will update these with MTU values it can see */ +__u32 global_bpf_mtu_xdp = 0; +__u32 global_bpf_mtu_tc = 0; + +SEC("xdp") +int xdp_use_helper_basic(struct xdp_md *ctx) +{ + __u32 mtu_len = 0; + + if (bpf_check_mtu(ctx, 0, &mtu_len, 0, 0)) + return XDP_ABORTED; + + return XDP_PASS; +} + +SEC("xdp") +int xdp_use_helper(struct xdp_md *ctx) +{ + int retval = XDP_PASS; /* Expected retval on successful test */ + __u32 mtu_len = 0; + __u32 ifindex = 0; + int delta = 0; + + /* When ifindex is zero, save net_device lookup and use ctx netdev */ + if (GLOBAL_USER_IFINDEX > 0) + ifindex = GLOBAL_USER_IFINDEX; + + if (bpf_check_mtu(ctx, ifindex, &mtu_len, delta, 0)) { + /* mtu_len is also valid when check fail */ + retval = XDP_ABORTED; + goto out; + } + + if (mtu_len != GLOBAL_USER_MTU) + retval = XDP_DROP; + +out: + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("xdp") +int xdp_exceed_mtu(struct xdp_md *ctx) +{ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + __u32 ifindex = GLOBAL_USER_IFINDEX; + __u32 data_len = data_end - data; + int retval = XDP_ABORTED; /* Fail */ + __u32 mtu_len = 0; + int delta; + int err; + + /* Exceed MTU with 1 via delta adjust */ + delta = GLOBAL_USER_MTU - (data_len - ETH_HLEN) + 1; + + err = bpf_check_mtu(ctx, ifindex, &mtu_len, delta, 0); + if (err) { + retval = XDP_PASS; /* Success in exceeding MTU check */ + if (err != BPF_MTU_CHK_RET_FRAG_NEEDED) + retval = XDP_DROP; + } + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("xdp") +int xdp_minus_delta(struct xdp_md *ctx) +{ + int retval = XDP_PASS; /* Expected retval on successful test */ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + __u32 ifindex = GLOBAL_USER_IFINDEX; + __u32 data_len = data_end - data; + __u32 mtu_len = 0; + int delta; + + /* Borderline test case: Minus delta exceeding packet length allowed */ + delta = -((data_len - ETH_HLEN) + 1); + + /* Minus length (adjusted via delta) still pass MTU check, other helpers + * are responsible for catching this, when doing actual size adjust + */ + if (bpf_check_mtu(ctx, ifindex, &mtu_len, delta, 0)) + retval = XDP_ABORTED; + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("xdp") +int xdp_input_len(struct xdp_md *ctx) +{ + int retval = XDP_PASS; /* Expected retval on successful test */ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + __u32 ifindex = GLOBAL_USER_IFINDEX; + __u32 data_len = data_end - data; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input len is L3, like MTU and iph->tot_len. + * Remember XDP data_len is L2. + */ + __u32 mtu_len = data_len - ETH_HLEN; + + if (bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0)) + retval = XDP_ABORTED; + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("xdp") +int xdp_input_len_exceed(struct xdp_md *ctx) +{ + int retval = XDP_ABORTED; /* Fail */ + __u32 ifindex = GLOBAL_USER_IFINDEX; + int err; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input length value is L3 size like MTU. + */ + __u32 mtu_len = GLOBAL_USER_MTU; + + mtu_len += 1; /* Exceed with 1 */ + + err = bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0); + if (err == BPF_MTU_CHK_RET_FRAG_NEEDED) + retval = XDP_PASS ; /* Success in exceeding MTU check */ + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("tc") +int tc_use_helper(struct __sk_buff *ctx) +{ + int retval = BPF_OK; /* Expected retval on successful test */ + __u32 mtu_len = 0; + int delta = 0; + + if (bpf_check_mtu(ctx, 0, &mtu_len, delta, 0)) { + retval = BPF_DROP; + goto out; + } + + if (mtu_len != GLOBAL_USER_MTU) + retval = BPF_REDIRECT; +out: + global_bpf_mtu_tc = mtu_len; + return retval; +} + +SEC("tc") +int tc_exceed_mtu(struct __sk_buff *ctx) +{ + __u32 ifindex = GLOBAL_USER_IFINDEX; + int retval = BPF_DROP; /* Fail */ + __u32 skb_len = ctx->len; + __u32 mtu_len = 0; + int delta; + int err; + + /* Exceed MTU with 1 via delta adjust */ + delta = GLOBAL_USER_MTU - (skb_len - ETH_HLEN) + 1; + + err = bpf_check_mtu(ctx, ifindex, &mtu_len, delta, 0); + if (err) { + retval = BPF_OK; /* Success in exceeding MTU check */ + if (err != BPF_MTU_CHK_RET_FRAG_NEEDED) + retval = BPF_DROP; + } + + global_bpf_mtu_tc = mtu_len; + return retval; +} + +SEC("tc") +int tc_exceed_mtu_da(struct __sk_buff *ctx) +{ + /* SKB Direct-Access variant */ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + __u32 ifindex = GLOBAL_USER_IFINDEX; + __u32 data_len = data_end - data; + int retval = BPF_DROP; /* Fail */ + __u32 mtu_len = 0; + int delta; + int err; + + /* Exceed MTU with 1 via delta adjust */ + delta = GLOBAL_USER_MTU - (data_len - ETH_HLEN) + 1; + + err = bpf_check_mtu(ctx, ifindex, &mtu_len, delta, 0); + if (err) { + retval = BPF_OK; /* Success in exceeding MTU check */ + if (err != BPF_MTU_CHK_RET_FRAG_NEEDED) + retval = BPF_DROP; + } + + global_bpf_mtu_tc = mtu_len; + return retval; +} + +SEC("tc") +int tc_minus_delta(struct __sk_buff *ctx) +{ + int retval = BPF_OK; /* Expected retval on successful test */ + __u32 ifindex = GLOBAL_USER_IFINDEX; + __u32 skb_len = ctx->len; + __u32 mtu_len = 0; + int delta; + + /* Borderline test case: Minus delta exceeding packet length allowed */ + delta = -((skb_len - ETH_HLEN) + 1); + + /* Minus length (adjusted via delta) still pass MTU check, other helpers + * are responsible for catching this, when doing actual size adjust + */ + if (bpf_check_mtu(ctx, ifindex, &mtu_len, delta, 0)) + retval = BPF_DROP; + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("tc") +int tc_input_len(struct __sk_buff *ctx) +{ + int retval = BPF_OK; /* Expected retval on successful test */ + __u32 ifindex = GLOBAL_USER_IFINDEX; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input length value is L3 size. + */ + __u32 mtu_len = GLOBAL_USER_MTU; + + if (bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0)) + retval = BPF_DROP; + + global_bpf_mtu_xdp = mtu_len; + return retval; +} + +SEC("tc") +int tc_input_len_exceed(struct __sk_buff *ctx) +{ + int retval = BPF_DROP; /* Fail */ + __u32 ifindex = GLOBAL_USER_IFINDEX; + int err; + + /* API allow user give length to check as input via mtu_len param, + * resulting MTU value is still output in mtu_len param after call. + * + * Input length value is L3 size like MTU. + */ + __u32 mtu_len = GLOBAL_USER_MTU; + + mtu_len += 1; /* Exceed with 1 */ + + err = bpf_check_mtu(ctx, ifindex, &mtu_len, 0, 0); + if (err == BPF_MTU_CHK_RET_FRAG_NEEDED) + retval = BPF_OK; /* Success in exceeding MTU check */ + + global_bpf_mtu_xdp = mtu_len; + return retval; +} |