diff options
Diffstat (limited to 'tools/lib/bpf/xsk.c')
| -rw-r--r-- | tools/lib/bpf/xsk.c | 316 |
1 files changed, 251 insertions, 65 deletions
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 526fc35c0b23..6061431ee04c 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -28,6 +28,7 @@ #include <sys/mman.h> #include <sys/socket.h> #include <sys/types.h> +#include <linux/if_link.h> #include "bpf.h" #include "libbpf.h" @@ -59,6 +60,8 @@ struct xsk_umem { int fd; int refcount; struct list_head ctx_list; + bool rx_ring_setup_done; + bool tx_ring_setup_done; }; struct xsk_ctx { @@ -70,8 +73,10 @@ struct xsk_ctx { int ifindex; struct list_head list; int prog_fd; + int link_fd; int xsks_map_fd; char ifname[IFNAMSIZ]; + bool has_bpf_link; }; struct xsk_socket { @@ -409,7 +414,7 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) static const int log_buf_size = 16 * 1024; struct xsk_ctx *ctx = xsk->ctx; char log_buf[log_buf_size]; - int err, prog_fd; + int prog_fd; /* This is the fallback C-program: * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) @@ -499,14 +504,41 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) return prog_fd; } - err = bpf_set_link_xdp_fd(xsk->ctx->ifindex, prog_fd, - xsk->config.xdp_flags); + ctx->prog_fd = prog_fd; + return 0; +} + +static int xsk_create_bpf_link(struct xsk_socket *xsk) +{ + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts); + struct xsk_ctx *ctx = xsk->ctx; + __u32 prog_id = 0; + int link_fd; + int err; + + err = bpf_get_link_xdp_id(ctx->ifindex, &prog_id, xsk->config.xdp_flags); if (err) { - close(prog_fd); + pr_warn("getting XDP prog id failed\n"); return err; } - ctx->prog_fd = prog_fd; + /* if there's a netlink-based XDP prog loaded on interface, bail out + * and ask user to do the removal by himself + */ + if (prog_id) { + pr_warn("Netlink-based XDP prog detected, please unload it in order to launch AF_XDP prog\n"); + return -EINVAL; + } + + opts.flags = xsk->config.xdp_flags & ~(XDP_FLAGS_UPDATE_IF_NOEXIST | XDP_FLAGS_REPLACE); + + link_fd = bpf_link_create(ctx->prog_fd, ctx->ifindex, BPF_XDP, &opts); + if (link_fd < 0) { + pr_warn("bpf_link_create failed: %s\n", strerror(errno)); + return link_fd; + } + + ctx->link_fd = link_fd; return 0; } @@ -625,7 +657,6 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) close(fd); } - err = 0; if (ctx->xsks_map_fd == -1) err = -ENOENT; @@ -642,6 +673,98 @@ static int xsk_set_bpf_maps(struct xsk_socket *xsk) &xsk->fd, 0); } +static int xsk_link_lookup(int ifindex, __u32 *prog_id, int *link_fd) +{ + struct bpf_link_info link_info; + __u32 link_len; + __u32 id = 0; + int err; + int fd; + + while (true) { + err = bpf_link_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + pr_warn("can't get next link: %s\n", strerror(errno)); + break; + } + + fd = bpf_link_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; + pr_warn("can't get link by id (%u): %s\n", id, strerror(errno)); + err = -errno; + break; + } + + link_len = sizeof(struct bpf_link_info); + memset(&link_info, 0, link_len); + err = bpf_obj_get_info_by_fd(fd, &link_info, &link_len); + if (err) { + pr_warn("can't get link info: %s\n", strerror(errno)); + close(fd); + break; + } + if (link_info.type == BPF_LINK_TYPE_XDP) { + if (link_info.xdp.ifindex == ifindex) { + *link_fd = fd; + if (prog_id) + *prog_id = link_info.prog_id; + break; + } + } + close(fd); + } + + return err; +} + +static bool xsk_probe_bpf_link(void) +{ + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts, + .flags = XDP_FLAGS_SKB_MODE); + struct bpf_load_program_attr prog_attr; + struct bpf_insn insns[2] = { + BPF_MOV64_IMM(BPF_REG_0, XDP_PASS), + BPF_EXIT_INSN() + }; + int prog_fd, link_fd = -1; + int ifindex_lo = 1; + bool ret = false; + int err; + + err = xsk_link_lookup(ifindex_lo, NULL, &link_fd); + if (err) + return ret; + + if (link_fd >= 0) + return true; + + memset(&prog_attr, 0, sizeof(prog_attr)); + prog_attr.prog_type = BPF_PROG_TYPE_XDP; + prog_attr.insns = insns; + prog_attr.insns_cnt = ARRAY_SIZE(insns); + prog_attr.license = "GPL"; + + prog_fd = bpf_load_program_xattr(&prog_attr, NULL, 0); + if (prog_fd < 0) + return ret; + + link_fd = bpf_link_create(prog_fd, ifindex_lo, BPF_XDP, &opts); + close(prog_fd); + + if (link_fd >= 0) { + ret = true; + close(link_fd); + } + + return ret; +} + static int xsk_create_xsk_struct(int ifindex, struct xsk_socket *xsk) { char ifname[IFNAMSIZ]; @@ -663,64 +786,108 @@ static int xsk_create_xsk_struct(int ifindex, struct xsk_socket *xsk) ctx->ifname[IFNAMSIZ - 1] = 0; xsk->ctx = ctx; + xsk->ctx->has_bpf_link = xsk_probe_bpf_link(); return 0; } -static int __xsk_setup_xdp_prog(struct xsk_socket *_xdp, - int *xsks_map_fd) +static int xsk_init_xdp_res(struct xsk_socket *xsk, + int *xsks_map_fd) { - struct xsk_socket *xsk = _xdp; struct xsk_ctx *ctx = xsk->ctx; - __u32 prog_id = 0; int err; - err = bpf_get_link_xdp_id(ctx->ifindex, &prog_id, - xsk->config.xdp_flags); + err = xsk_create_bpf_maps(xsk); if (err) return err; - if (!prog_id) { - err = xsk_create_bpf_maps(xsk); - if (err) - return err; + err = xsk_load_xdp_prog(xsk); + if (err) + goto err_load_xdp_prog; - err = xsk_load_xdp_prog(xsk); - if (err) { - goto err_load_xdp_prog; - } - } else { - ctx->prog_fd = bpf_prog_get_fd_by_id(prog_id); - if (ctx->prog_fd < 0) - return -errno; - err = xsk_lookup_bpf_maps(xsk); - if (err) { - close(ctx->prog_fd); - return err; - } - } + if (ctx->has_bpf_link) + err = xsk_create_bpf_link(xsk); + else + err = bpf_set_link_xdp_fd(xsk->ctx->ifindex, ctx->prog_fd, + xsk->config.xdp_flags); - if (xsk->rx) { - err = xsk_set_bpf_maps(xsk); - if (err) { - if (!prog_id) { - goto err_set_bpf_maps; - } else { - close(ctx->prog_fd); - return err; - } - } - } - if (xsks_map_fd) - *xsks_map_fd = ctx->xsks_map_fd; + if (err) + goto err_attach_xdp_prog; - return 0; + if (!xsk->rx) + return err; + + err = xsk_set_bpf_maps(xsk); + if (err) + goto err_set_bpf_maps; + + return err; err_set_bpf_maps: + if (ctx->has_bpf_link) + close(ctx->link_fd); + else + bpf_set_link_xdp_fd(ctx->ifindex, -1, 0); +err_attach_xdp_prog: close(ctx->prog_fd); - bpf_set_link_xdp_fd(ctx->ifindex, -1, 0); err_load_xdp_prog: xsk_delete_bpf_maps(xsk); + return err; +} + +static int xsk_lookup_xdp_res(struct xsk_socket *xsk, int *xsks_map_fd, int prog_id) +{ + struct xsk_ctx *ctx = xsk->ctx; + int err; + + ctx->prog_fd = bpf_prog_get_fd_by_id(prog_id); + if (ctx->prog_fd < 0) { + err = -errno; + goto err_prog_fd; + } + err = xsk_lookup_bpf_maps(xsk); + if (err) + goto err_lookup_maps; + + if (!xsk->rx) + return err; + + err = xsk_set_bpf_maps(xsk); + if (err) + goto err_set_maps; + + return err; + +err_set_maps: + close(ctx->xsks_map_fd); +err_lookup_maps: + close(ctx->prog_fd); +err_prog_fd: + if (ctx->has_bpf_link) + close(ctx->link_fd); + return err; +} + +static int __xsk_setup_xdp_prog(struct xsk_socket *_xdp, int *xsks_map_fd) +{ + struct xsk_socket *xsk = _xdp; + struct xsk_ctx *ctx = xsk->ctx; + __u32 prog_id = 0; + int err; + + if (ctx->has_bpf_link) + err = xsk_link_lookup(ctx->ifindex, &prog_id, &ctx->link_fd); + else + err = bpf_get_link_xdp_id(ctx->ifindex, &prog_id, xsk->config.xdp_flags); + + if (err) + return err; + + err = !prog_id ? xsk_init_xdp_res(xsk, xsks_map_fd) : + xsk_lookup_xdp_res(xsk, xsks_map_fd, prog_id); + + if (!err && xsks_map_fd) + *xsks_map_fd = ctx->xsks_map_fd; return err; } @@ -743,26 +910,30 @@ static struct xsk_ctx *xsk_get_ctx(struct xsk_umem *umem, int ifindex, return NULL; } -static void xsk_put_ctx(struct xsk_ctx *ctx) +static void xsk_put_ctx(struct xsk_ctx *ctx, bool unmap) { struct xsk_umem *umem = ctx->umem; struct xdp_mmap_offsets off; int err; - if (--ctx->refcount == 0) { - err = xsk_get_mmap_offsets(umem->fd, &off); - if (!err) { - munmap(ctx->fill->ring - off.fr.desc, - off.fr.desc + umem->config.fill_size * - sizeof(__u64)); - munmap(ctx->comp->ring - off.cr.desc, - off.cr.desc + umem->config.comp_size * - sizeof(__u64)); - } + if (--ctx->refcount) + return; - list_del(&ctx->list); - free(ctx); - } + if (!unmap) + goto out_free; + + err = xsk_get_mmap_offsets(umem->fd, &off); + if (err) + goto out_free; + + munmap(ctx->fill->ring - off.fr.desc, off.fr.desc + umem->config.fill_size * + sizeof(__u64)); + munmap(ctx->comp->ring - off.cr.desc, off.cr.desc + umem->config.comp_size * + sizeof(__u64)); + +out_free: + list_del(&ctx->list); + free(ctx); } static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, @@ -797,8 +968,6 @@ static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, memcpy(ctx->ifname, ifname, IFNAMSIZ - 1); ctx->ifname[IFNAMSIZ - 1] = '\0'; - umem->fill_save = NULL; - umem->comp_save = NULL; ctx->fill = fill; ctx->comp = comp; list_add(&ctx->list, &umem->ctx_list); @@ -848,6 +1017,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, struct xsk_ring_cons *comp, const struct xsk_socket_config *usr_config) { + bool unmap, rx_setup_done = false, tx_setup_done = false; void *rx_map = NULL, *tx_map = NULL; struct sockaddr_xdp sxdp = {}; struct xdp_mmap_offsets off; @@ -858,6 +1028,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, if (!umem || !xsk_ptr || !(rx || tx)) return -EFAULT; + unmap = umem->fill_save != fill; + xsk = calloc(1, sizeof(*xsk)); if (!xsk) return -ENOMEM; @@ -881,6 +1053,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } } else { xsk->fd = umem->fd; + rx_setup_done = umem->rx_ring_setup_done; + tx_setup_done = umem->tx_ring_setup_done; } ctx = xsk_get_ctx(umem, ifindex, queue_id); @@ -898,8 +1072,9 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } } xsk->ctx = ctx; + xsk->ctx->has_bpf_link = xsk_probe_bpf_link(); - if (rx) { + if (rx && !rx_setup_done) { err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING, &xsk->config.rx_size, sizeof(xsk->config.rx_size)); @@ -907,8 +1082,10 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, err = -errno; goto out_put_ctx; } + if (xsk->fd == umem->fd) + umem->rx_ring_setup_done = true; } - if (tx) { + if (tx && !tx_setup_done) { err = setsockopt(xsk->fd, SOL_XDP, XDP_TX_RING, &xsk->config.tx_size, sizeof(xsk->config.tx_size)); @@ -916,6 +1093,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, err = -errno; goto out_put_ctx; } + if (xsk->fd == umem->fd) + umem->rx_ring_setup_done = true; } err = xsk_get_mmap_offsets(xsk->fd, &off); @@ -994,6 +1173,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } *xsk_ptr = xsk; + umem->fill_save = NULL; + umem->comp_save = NULL; return 0; out_mmap_tx: @@ -1005,7 +1186,7 @@ out_mmap_rx: munmap(rx_map, off.rx.desc + xsk->config.rx_size * sizeof(struct xdp_desc)); out_put_ctx: - xsk_put_ctx(ctx); + xsk_put_ctx(ctx, unmap); out_socket: if (--umem->refcount) close(xsk->fd); @@ -1019,6 +1200,9 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, struct xsk_ring_cons *rx, struct xsk_ring_prod *tx, const struct xsk_socket_config *usr_config) { + if (!umem) + return -EFAULT; + return xsk_socket__create_shared(xsk_ptr, ifname, queue_id, umem, rx, tx, umem->fill_save, umem->comp_save, usr_config); @@ -1054,6 +1238,8 @@ void xsk_socket__delete(struct xsk_socket *xsk) if (ctx->prog_fd != -1) { xsk_delete_bpf_maps(xsk); close(ctx->prog_fd); + if (ctx->has_bpf_link) + close(ctx->link_fd); } err = xsk_get_mmap_offsets(xsk->fd, &off); @@ -1068,7 +1254,7 @@ void xsk_socket__delete(struct xsk_socket *xsk) } } - xsk_put_ctx(ctx); + xsk_put_ctx(ctx, true); umem->refcount--; /* Do not close an fd that also has an associated umem connected |