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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:24:08 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:24:08 +0000 |
commit | f449f278dd3c70e479a035f50a9bb817a9b433ba (patch) | |
tree | 8ca2bfb785dda9bb4d573acdf9b42aea9cd51383 /src/libknot/xdp/bpf-user.c | |
parent | Initial commit. (diff) | |
download | knot-f449f278dd3c70e479a035f50a9bb817a9b433ba.tar.xz knot-f449f278dd3c70e479a035f50a9bb817a9b433ba.zip |
Adding upstream version 3.2.6.upstream/3.2.6upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/libknot/xdp/bpf-user.c | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/src/libknot/xdp/bpf-user.c b/src/libknot/xdp/bpf-user.c new file mode 100644 index 0000000..a0c8bae --- /dev/null +++ b/src/libknot/xdp/bpf-user.c @@ -0,0 +1,313 @@ +/* Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#include <bpf/bpf.h> +#include <linux/if_link.h> +#include <net/if.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "libknot/endian.h" +#include "libknot/error.h" +#include "libknot/xdp/bpf-kernel-obj.h" +#include "libknot/xdp/bpf-user.h" +#include "libknot/xdp/eth.h" +#include "contrib/openbsd/strlcpy.h" + +#define NO_BPF_MAPS 2 + +static inline bool IS_ERR_OR_NULL(const void *ptr) +{ + return (ptr == NULL) || (unsigned long)ptr >= (unsigned long)-4095; +} + +static int prog_load(struct bpf_object **pobj, int *prog_fd) +{ + struct bpf_program *prog, *first_prog = NULL; + struct bpf_object *obj; + + obj = bpf_object__open_mem(bpf_kernel_o, bpf_kernel_o_len, NULL); + if (IS_ERR_OR_NULL(obj)) { + return KNOT_ENOENT; + } + + bpf_object__for_each_program(prog, obj) { + bpf_program__set_type(prog, BPF_PROG_TYPE_XDP); + if (first_prog == NULL) { + first_prog = prog; + } + } + + if (first_prog == NULL) { + bpf_object__close(obj); + return KNOT_ENOENT; + } + + int ret = bpf_object__load(obj); + if (ret != 0) { + bpf_object__close(obj); + return KNOT_EINVAL; + } + + *pobj = obj; + *prog_fd = bpf_program__fd(first_prog); + + return KNOT_EOK; +} + +static int ensure_prog(struct kxsk_iface *iface, bool overwrite) +{ + if (bpf_kernel_o_len < 2) { + return KNOT_ENOTSUP; + } + + /* Use libbpf for extracting BPF byte-code from BPF-ELF object, and + * loading this into the kernel via bpf-syscall. */ + int prog_fd; + int ret = prog_load(&iface->prog_obj, &prog_fd); + if (ret != KNOT_EOK) { + return KNOT_EPROGRAM; + } + +#if USE_LIBXDP + ret = bpf_xdp_attach(iface->if_index, prog_fd, + overwrite ? 0 : XDP_FLAGS_UPDATE_IF_NOEXIST, NULL); +#else + ret = bpf_set_link_xdp_fd(iface->if_index, prog_fd, + overwrite ? 0 : XDP_FLAGS_UPDATE_IF_NOEXIST); +#endif + if (ret != 0) { + close(prog_fd); + } + if (ret == -EBUSY && !overwrite) { // We try accepting the present program. + uint32_t prog_id = 0; +#if USE_LIBXDP + ret = bpf_xdp_query_id(iface->if_index, 0, &prog_id); +#else + ret = bpf_get_link_xdp_id(iface->if_index, &prog_id, 0); +#endif + if (ret == 0 && prog_id != 0) { + ret = prog_fd = bpf_prog_get_fd_by_id(prog_id); + } + } + if (ret < 0) { + return KNOT_EFD; + } else { + return prog_fd; + } +} + +static void unget_bpf_maps(struct kxsk_iface *iface) +{ + if (iface->opts_map_fd >= 0) { + close(iface->opts_map_fd); + } + if (iface->xsks_map_fd >= 0) { + close(iface->xsks_map_fd); + } + iface->opts_map_fd = iface->xsks_map_fd = -1; +} + +/*! + * /brief Get FDs for the two maps and assign them into xsk_info-> fields. + * + * Inspired by xsk_lookup_bpf_maps() from libbpf before qidconf_map elimination. + */ +static int get_bpf_maps(int prog_fd, struct kxsk_iface *iface) +{ + uint32_t *map_ids = calloc(NO_BPF_MAPS, sizeof(*map_ids)); + if (map_ids == NULL) { + return KNOT_ENOMEM; + } + + struct bpf_prog_info prog_info = { + .nr_map_ids = NO_BPF_MAPS, + .map_ids = (__u64)(unsigned long)map_ids, + }; + + uint32_t prog_len = sizeof(struct bpf_prog_info); + int ret = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &prog_len); + if (ret != 0) { + free(map_ids); + return ret; + } + + for (int i = 0; i < NO_BPF_MAPS; ++i) { + int fd = bpf_map_get_fd_by_id(map_ids[i]); + if (fd < 0) { + continue; + } + + struct bpf_map_info map_info = { 0 }; + uint32_t map_len = sizeof(struct bpf_map_info); + ret = bpf_obj_get_info_by_fd(fd, &map_info, &map_len); + if (ret != 0) { + close(fd); + continue; + } + + if (strcmp(map_info.name, "opts_map") == 0) { + iface->opts_map_fd = fd; + continue; + } + + if (strcmp(map_info.name, "xsks_map") == 0) { + iface->xsks_map_fd = fd; + continue; + } + + close(fd); + } + + if (iface->opts_map_fd < 0 || iface->xsks_map_fd < 0) { + unget_bpf_maps(iface); + free(map_ids); + return KNOT_ENOENT; + } + + free(map_ids); + return KNOT_EOK; +} + +int kxsk_socket_start(const struct kxsk_iface *iface, knot_xdp_filter_flag_t flags, + uint16_t udp_port, uint16_t quic_port, struct xsk_socket *xsk) +{ + if (iface == NULL || xsk == NULL) { + return KNOT_EINVAL; + } + + int fd = xsk_socket__fd(xsk); + int ret = bpf_map_update_elem(iface->xsks_map_fd, &iface->if_queue, &fd, 0); + if (ret != 0) { + return ret; + } + + knot_xdp_opts_t opts = { + .flags = flags | KNOT_XDP_FILTER_ON, + .udp_port = udp_port, + .quic_port = quic_port, + }; + + ret = bpf_map_update_elem(iface->opts_map_fd, &iface->if_queue, &opts, 0); + if (ret != 0) { + (void)bpf_map_delete_elem(iface->xsks_map_fd, &iface->if_queue); + } + + return ret; +} + +void kxsk_socket_stop(const struct kxsk_iface *iface) +{ + if (iface == NULL) { + return; + } + + knot_xdp_opts_t opts = { 0 }; + + (void)bpf_map_update_elem(iface->opts_map_fd, &iface->if_queue, &opts, 0); + (void)bpf_map_delete_elem(iface->xsks_map_fd, &iface->if_queue); +} + +int kxsk_iface_new(const char *if_name, unsigned if_queue, knot_xdp_load_bpf_t load_bpf, + struct kxsk_iface **out_iface) +{ + if (if_name == NULL || out_iface == NULL) { + return KNOT_EINVAL; + } + + struct kxsk_iface *iface = calloc(1, sizeof(*iface) + IFNAMSIZ); + if (iface == NULL) { + return KNOT_ENOMEM; + } + iface->if_name = (char *)(iface + 1); + strlcpy((char *)iface->if_name, if_name, IFNAMSIZ); + iface->if_index = if_nametoindex(if_name); + if (iface->if_index == 0) { + free(iface); + return KNOT_EINVAL; + } + iface->if_queue = if_queue; + iface->opts_map_fd = iface->xsks_map_fd = -1; + + int ret; + switch (load_bpf) { + case KNOT_XDP_LOAD_BPF_NEVER: + (void)0; + uint32_t prog_id = 0; +#if USE_LIBXDP + ret = bpf_xdp_query_id(iface->if_index, 0, &prog_id); +#else + ret = bpf_get_link_xdp_id(iface->if_index, &prog_id, 0); +#endif + if (ret == 0) { + if (prog_id == 0) { + ret = KNOT_EPROGRAM; + } else { + ret = bpf_prog_get_fd_by_id(prog_id); + } + } + break; + case KNOT_XDP_LOAD_BPF_ALWAYS_UNLOAD: +#if USE_LIBXDP + (void)bpf_xdp_detach(iface->if_index, 0, NULL); +#else + (void)bpf_set_link_xdp_fd(iface->if_index, -1, 0); +#endif + sleep(1); + // FALLTHROUGH + case KNOT_XDP_LOAD_BPF_ALWAYS: + ret = ensure_prog(iface, true); + break; + case KNOT_XDP_LOAD_BPF_MAYBE: + ret = ensure_prog(iface, false); + break; + default: + return KNOT_EINVAL; + } + + if (ret >= 0) { + ret = get_bpf_maps(ret, iface); + } + if (ret < 0) { + free(iface); + return ret; + } + + knot_xdp_mode_t mode = knot_eth_xdp_mode(iface->if_index); + if (mode == KNOT_XDP_MODE_NONE) { + free(iface); + return KNOT_ENOTSUP; + } + + *out_iface = iface; + return KNOT_EOK; +} + +void kxsk_iface_free(struct kxsk_iface *iface) +{ + if (iface == NULL) { + return; + } + + unget_bpf_maps(iface); + + if (iface->prog_obj != NULL) { + bpf_object__close(iface->prog_obj); + } + + free(iface); +} |