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In this sample we will set the pkt's src mac to egress's mac address. The xdp_prog will be attached when -X option supplied. Signed-off-by: Hangbin Liu Acked-by: Yonghong Song --- v7: a) use bpf_object__find_program_by_name() instad of bpf_object__find_program_by_title() b) set default devmap fd to 0 v6: no code update, only rebase the code on latest bpf-next v5: a) close fd when err out in get_mac_addr() b) exit program when both -S and -X supplied. v4: a) Update get_mac_addr socket create b) Load dummy prog regardless of 2nd xdp prog on egress v3: a) modify the src mac address based on egress mac v2: a) use pkt counter instead of IP ttl modification on egress program b) make the egress program selectable by option -X --- samples/bpf/xdp_redirect_map_kern.c | 77 +++++++++++++-- samples/bpf/xdp_redirect_map_user.c | 141 ++++++++++++++++++++++++---- 2 files changed, 192 insertions(+), 26 deletions(-) diff --git a/samples/bpf/xdp_redirect_map_kern.c b/samples/bpf/xdp_redirect_map_kern.c index 6489352ab7a4..1a3bac75ba81 100644 --- a/samples/bpf/xdp_redirect_map_kern.c +++ b/samples/bpf/xdp_redirect_map_kern.c @@ -19,12 +19,22 @@ #include #include +/* The 2nd xdp prog on egress does not support skb mode, so we define two + * maps, tx_port_general and tx_port_native. + */ struct { __uint(type, BPF_MAP_TYPE_DEVMAP); __uint(key_size, sizeof(int)); __uint(value_size, sizeof(int)); __uint(max_entries, 100); -} tx_port SEC(".maps"); +} tx_port_general SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_DEVMAP); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(struct bpf_devmap_val)); + __uint(max_entries, 100); +} tx_port_native SEC(".maps"); /* Count RX packets, as XDP bpf_prog doesn't get direct TX-success * feedback. Redirect TX errors can be caught via a tracepoint. @@ -36,6 +46,14 @@ struct { __uint(max_entries, 1); } rxcnt SEC(".maps"); +/* map to store egress interface mac address */ +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, u32); + __type(value, __be64); + __uint(max_entries, 1); +} tx_mac SEC(".maps"); + static void swap_src_dst_mac(void *data) { unsigned short *p = data; @@ -52,17 +70,16 @@ static void swap_src_dst_mac(void *data) p[5] = dst[2]; } -SEC("xdp_redirect_map") -int xdp_redirect_map_prog(struct xdp_md *ctx) +static int xdp_redirect_map(struct xdp_md *ctx, void *redirect_map) { void *data_end = (void *)(long)ctx->data_end; void *data = (void *)(long)ctx->data; struct ethhdr *eth = data; int rc = XDP_DROP; - int vport, port = 0, m = 0; long *value; u32 key = 0; u64 nh_off; + int vport; nh_off = sizeof(*eth); if (data + nh_off > data_end) @@ -73,13 +90,61 @@ int xdp_redirect_map_prog(struct xdp_md *ctx) /* count packet in global counter */ value = bpf_map_lookup_elem(&rxcnt, &key); - if (value) + if (value) { *value += 1; + if (*value % 2 == 1) + vport = 1; + } swap_src_dst_mac(data); /* send packet out physical port */ - return bpf_redirect_map(&tx_port, vport, 0); + return bpf_redirect_map(redirect_map, vport, 0); +} + +static int xdp_redirect_map_egress(struct xdp_md *ctx, unsigned char *mac) +{ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + struct ethhdr *eth = data; + u32 key = 0; + u64 nh_off; + + nh_off = sizeof(*eth); + if (data + nh_off > data_end) + return XDP_DROP; + + __builtin_memcpy(eth->h_source, mac, ETH_ALEN); + + return XDP_PASS; +} + +SEC("xdp_redirect_general") +int xdp_redirect_map_general(struct xdp_md *ctx) +{ + return xdp_redirect_map(ctx, &tx_port_general); +} + +SEC("xdp_redirect_native") +int xdp_redirect_map_native(struct xdp_md *ctx) +{ + return xdp_redirect_map(ctx, &tx_port_native); +} + +/* This program will set src mac to 00:00:00:00:00:01 */ +SEC("xdp_devmap/map_prog_0") +int xdp_redirect_map_egress_0(struct xdp_md *ctx) +{ + unsigned char mac[6] = {0x0, 0x0, 0x0, 0x0, 0x0, 0x1}; + return xdp_redirect_map_egress(ctx, mac); +} + +/* This program will set src mac to 00:00:00:00:01:01 */ +SEC("xdp_devmap/map_prog_1") +int xdp_redirect_map_egress_1(struct xdp_md *ctx) +{ + unsigned char mac[6] = {0x0, 0x0, 0x0, 0x0, 0x1, 0x1}; + return xdp_redirect_map_egress(ctx, mac); } /* Redirect require an XDP bpf_prog loaded on the TX device */ diff --git a/samples/bpf/xdp_redirect_map_user.c b/samples/bpf/xdp_redirect_map_user.c index 31131b6e7782..c2c06aa2ecad 100644 --- a/samples/bpf/xdp_redirect_map_user.c +++ b/samples/bpf/xdp_redirect_map_user.c @@ -14,6 +14,10 @@ #include #include #include +#include +#include +#include +#include #include "bpf_util.h" #include @@ -22,6 +26,7 @@ static int ifindex_in; static int ifindex_out; static bool ifindex_out_xdp_dummy_attached = true; +static bool xdp_devmap_attached = false; static __u32 prog_id; static __u32 dummy_prog_id; @@ -83,6 +88,32 @@ static void poll_stats(int interval, int ifindex) } } +static int get_mac_addr(unsigned int ifindex_out, void *mac_addr) +{ + char ifname[IF_NAMESIZE]; + struct ifreq ifr; + int fd, ret = -1; + + fd = socket(AF_INET, SOCK_DGRAM, 0); + if (fd < 0) + return ret; + + if (!if_indextoname(ifindex_out, ifname)) + goto err_out; + + strcpy(ifr.ifr_name, ifname); + + if (ioctl(fd, SIOCGIFHWADDR, &ifr) != 0) + goto err_out; + + memcpy(mac_addr, ifr.ifr_hwaddr.sa_data, 6 * sizeof(char)); + ret = 0; + +err_out: + close(fd); + return ret; +} + static void usage(const char *prog) { fprintf(stderr, @@ -90,24 +121,27 @@ static void usage(const char *prog) "OPTS:\n" " -S use skb-mode\n" " -N enforce native mode\n" - " -F force loading prog\n", + " -F force loading prog\n" + " -X load xdp program on egress\n", prog); } int main(int argc, char **argv) { struct bpf_prog_load_attr prog_load_attr = { - .prog_type = BPF_PROG_TYPE_XDP, + .prog_type = BPF_PROG_TYPE_UNSPEC, }; - struct bpf_program *prog, *dummy_prog; + struct bpf_program *prog, *dummy_prog, *devmap_prog; + int devmap_prog_fd_0 = 0, devmap_prog_fd_1 = 0; + int prog_fd, dummy_prog_fd; + int tx_port_map_fd, tx_mac_map_fd; + struct bpf_devmap_val devmap_val; struct bpf_prog_info info = {}; __u32 info_len = sizeof(info); - int prog_fd, dummy_prog_fd; - const char *optstr = "FSN"; + const char *optstr = "FSNX"; struct bpf_object *obj; int ret, opt, key = 0; char filename[256]; - int tx_port_map_fd; while ((opt = getopt(argc, argv, optstr)) != -1) { switch (opt) { @@ -120,14 +154,21 @@ int main(int argc, char **argv) case 'F': xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST; break; + case 'X': + xdp_devmap_attached = true; + break; default: usage(basename(argv[0])); return 1; } } - if (!(xdp_flags & XDP_FLAGS_SKB_MODE)) + if (!(xdp_flags & XDP_FLAGS_SKB_MODE)) { xdp_flags |= XDP_FLAGS_DRV_MODE; + } else if (xdp_devmap_attached) { + printf("Load xdp program on egress with SKB mode not supported yet\n"); + return 1; + } if (optind == argc) { printf("usage: %s _IN _OUT\n", argv[0]); @@ -150,24 +191,28 @@ int main(int argc, char **argv) if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd)) return 1; - prog = bpf_program__next(NULL, obj); - dummy_prog = bpf_program__next(prog, obj); - if (!prog || !dummy_prog) { - printf("finding a prog in obj file failed\n"); - return 1; + if (xdp_flags & XDP_FLAGS_SKB_MODE) { + prog = bpf_object__find_program_by_name(obj, "xdp_redirect_map_general"); + tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port_general"); + } else { + prog = bpf_object__find_program_by_name(obj, "xdp_redirect_map_native"); + tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port_native"); } - /* bpf_prog_load_xattr gives us the pointer to first prog's fd, - * so we're missing only the fd for dummy prog - */ + dummy_prog = bpf_object__find_program_by_name(obj, "xdp_redirect_dummy_prog"); + if (!prog || dummy_prog < 0 || tx_port_map_fd < 0) { + printf("finding prog/dummy_prog/tx_port_map in obj file failed\n"); + goto out; + } + prog_fd = bpf_program__fd(prog); dummy_prog_fd = bpf_program__fd(dummy_prog); - if (prog_fd < 0 || dummy_prog_fd < 0) { + if (prog_fd < 0 || dummy_prog_fd < 0 || tx_port_map_fd < 0) { printf("bpf_prog_load_xattr: %s\n", strerror(errno)); return 1; } - tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port"); + tx_mac_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_mac"); rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt"); - if (tx_port_map_fd < 0 || rxcnt_map_fd < 0) { + if (tx_mac_map_fd < 0 || rxcnt_map_fd < 0) { printf("bpf_object__find_map_fd_by_name failed\n"); return 1; } @@ -199,11 +244,67 @@ int main(int argc, char **argv) } dummy_prog_id = info.id; + /* Load 2nd xdp prog on egress. */ + if (xdp_devmap_attached) { + unsigned char mac_addr[6]; + + devmap_prog = bpf_object__find_program_by_name(obj, "xdp_redirect_map_egress_0"); + if (!devmap_prog) { + printf("finding devmap_prog in obj file failed\n"); + goto out; + } + devmap_prog_fd_0 = bpf_program__fd(devmap_prog); + if (devmap_prog_fd_0 < 0) { + printf("finding devmap_prog fd failed\n"); + goto out; + } + + devmap_prog = bpf_object__find_program_by_name(obj, "xdp_redirect_map_egress_1"); + if (!devmap_prog) { + printf("finding devmap_prog in obj file failed\n"); + goto out; + } + devmap_prog_fd_1 = bpf_program__fd(devmap_prog); + if (devmap_prog_fd_1 < 0) { + printf("finding devmap_prog fd failed\n"); + goto out; + } + + if (get_mac_addr(ifindex_out, mac_addr) < 0) { + printf("get interface %d mac failed\n", ifindex_out); + goto out; + } + + ret = bpf_map_update_elem(tx_mac_map_fd, &key, mac_addr, 0); + if (ret) { + perror("bpf_update_elem tx_mac_map_fd"); + goto out; + } + } + + signal(SIGINT, int_exit); signal(SIGTERM, int_exit); - /* populate virtual to physical port map */ - ret = bpf_map_update_elem(tx_port_map_fd, &key, &ifindex_out, 0); + /* devmap prog 0 will set src mac to 00:00:00:00:00:01 + * if 2nd xdp prog attached on egress + */ + key = 0; + devmap_val.ifindex = ifindex_out; + devmap_val.bpf_prog.fd = devmap_prog_fd_0; + ret = bpf_map_update_elem(tx_port_map_fd, &key, &devmap_val, 0); + if (ret) { + perror("bpf_update_elem"); + goto out; + } + + /* devmap prog 1 will set src mac to 00:00:00:00:01:01 + * if 2nd xdp prog attached on egress + */ + key = 1; + devmap_val.ifindex = ifindex_out; + devmap_val.bpf_prog.fd = devmap_prog_fd_1; + ret = bpf_map_update_elem(tx_port_map_fd, &key, &devmap_val, 0); if (ret) { perror("bpf_update_elem"); goto out;