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-rw-r--r--tools/lib/bpf/xsk.c130
1 files changed, 106 insertions, 24 deletions
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index a902838f9fcc..74d84f36a5b2 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -73,6 +73,21 @@ struct xsk_nl_info {
int fd;
};
+/* Up until and including Linux 5.3 */
+struct xdp_ring_offset_v1 {
+ __u64 producer;
+ __u64 consumer;
+ __u64 desc;
+};
+
+/* Up until and including Linux 5.3 */
+struct xdp_mmap_offsets_v1 {
+ struct xdp_ring_offset_v1 rx;
+ struct xdp_ring_offset_v1 tx;
+ struct xdp_ring_offset_v1 fr;
+ struct xdp_ring_offset_v1 cr;
+};
+
int xsk_umem__fd(const struct xsk_umem *umem)
{
return umem ? umem->fd : -EINVAL;
@@ -133,6 +148,58 @@ static int xsk_set_xdp_socket_config(struct xsk_socket_config *cfg,
return 0;
}
+static void xsk_mmap_offsets_v1(struct xdp_mmap_offsets *off)
+{
+ struct xdp_mmap_offsets_v1 off_v1;
+
+ /* getsockopt on a kernel <= 5.3 has no flags fields.
+ * Copy over the offsets to the correct places in the >=5.4 format
+ * and put the flags where they would have been on that kernel.
+ */
+ memcpy(&off_v1, off, sizeof(off_v1));
+
+ off->rx.producer = off_v1.rx.producer;
+ off->rx.consumer = off_v1.rx.consumer;
+ off->rx.desc = off_v1.rx.desc;
+ off->rx.flags = off_v1.rx.consumer + sizeof(__u32);
+
+ off->tx.producer = off_v1.tx.producer;
+ off->tx.consumer = off_v1.tx.consumer;
+ off->tx.desc = off_v1.tx.desc;
+ off->tx.flags = off_v1.tx.consumer + sizeof(__u32);
+
+ off->fr.producer = off_v1.fr.producer;
+ off->fr.consumer = off_v1.fr.consumer;
+ off->fr.desc = off_v1.fr.desc;
+ off->fr.flags = off_v1.fr.consumer + sizeof(__u32);
+
+ off->cr.producer = off_v1.cr.producer;
+ off->cr.consumer = off_v1.cr.consumer;
+ off->cr.desc = off_v1.cr.desc;
+ off->cr.flags = off_v1.cr.consumer + sizeof(__u32);
+}
+
+static int xsk_get_mmap_offsets(int fd, struct xdp_mmap_offsets *off)
+{
+ socklen_t optlen;
+ int err;
+
+ optlen = sizeof(*off);
+ err = getsockopt(fd, SOL_XDP, XDP_MMAP_OFFSETS, off, &optlen);
+ if (err)
+ return err;
+
+ if (optlen == sizeof(*off))
+ return 0;
+
+ if (optlen == sizeof(struct xdp_mmap_offsets_v1)) {
+ xsk_mmap_offsets_v1(off);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area,
__u64 size, struct xsk_ring_prod *fill,
struct xsk_ring_cons *comp,
@@ -141,7 +208,6 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area,
struct xdp_mmap_offsets off;
struct xdp_umem_reg mr;
struct xsk_umem *umem;
- socklen_t optlen;
void *map;
int err;
@@ -163,6 +229,7 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area,
umem->umem_area = umem_area;
xsk_set_umem_config(&umem->config, usr_config);
+ memset(&mr, 0, sizeof(mr));
mr.addr = (uintptr_t)umem_area;
mr.len = size;
mr.chunk_size = umem->config.frame_size;
@@ -189,8 +256,7 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area,
goto out_socket;
}
- optlen = sizeof(off);
- err = getsockopt(umem->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);
+ err = xsk_get_mmap_offsets(umem->fd, &off);
if (err) {
err = -errno;
goto out_socket;
@@ -273,33 +339,55 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk)
/* This is the C-program:
* SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx)
* {
- * int index = ctx->rx_queue_index;
+ * int ret, index = ctx->rx_queue_index;
*
* // A set entry here means that the correspnding queue_id
* // has an active AF_XDP socket bound to it.
+ * ret = bpf_redirect_map(&xsks_map, index, XDP_PASS);
+ * if (ret > 0)
+ * return ret;
+ *
+ * // Fallback for pre-5.3 kernels, not supporting default
+ * // action in the flags parameter.
* if (bpf_map_lookup_elem(&xsks_map, &index))
* return bpf_redirect_map(&xsks_map, index, 0);
- *
* return XDP_PASS;
* }
*/
struct bpf_insn prog[] = {
- /* r1 = *(u32 *)(r1 + 16) */
- BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1, 16),
- /* *(u32 *)(r10 - 4) = r1 */
- BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_1, -4),
+ /* r2 = *(u32 *)(r1 + 16) */
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 16),
+ /* *(u32 *)(r10 - 4) = r2 */
+ BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -4),
+ /* r1 = xskmap[] */
+ BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd),
+ /* r3 = XDP_PASS */
+ BPF_MOV64_IMM(BPF_REG_3, 2),
+ /* call bpf_redirect_map */
+ BPF_EMIT_CALL(BPF_FUNC_redirect_map),
+ /* if w0 != 0 goto pc+13 */
+ BPF_JMP32_IMM(BPF_JSGT, BPF_REG_0, 0, 13),
+ /* r2 = r10 */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ /* r2 += -4 */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),
+ /* r1 = xskmap[] */
BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd),
+ /* call bpf_map_lookup_elem */
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+ /* r1 = r0 */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
- BPF_MOV32_IMM(BPF_REG_0, 2),
- /* if r1 == 0 goto +5 */
+ /* r0 = XDP_PASS */
+ BPF_MOV64_IMM(BPF_REG_0, 2),
+ /* if r1 == 0 goto pc+5 */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 5),
/* r2 = *(u32 *)(r10 - 4) */
- BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd),
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_10, -4),
- BPF_MOV32_IMM(BPF_REG_3, 0),
+ /* r1 = xskmap[] */
+ BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd),
+ /* r3 = 0 */
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ /* call bpf_redirect_map */
BPF_EMIT_CALL(BPF_FUNC_redirect_map),
/* The jumps are to this instruction */
BPF_EXIT_INSN(),
@@ -310,7 +398,7 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk)
"LGPL-2.1 or BSD-2-Clause", 0, log_buf,
log_buf_size);
if (prog_fd < 0) {
- pr_warning("BPF log buffer:\n%s", log_buf);
+ pr_warn("BPF log buffer:\n%s", log_buf);
return prog_fd;
}
@@ -491,14 +579,13 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
struct sockaddr_xdp sxdp = {};
struct xdp_mmap_offsets off;
struct xsk_socket *xsk;
- socklen_t optlen;
int err;
if (!umem || !xsk_ptr || !rx || !tx)
return -EFAULT;
if (umem->refcount) {
- pr_warning("Error: shared umems not supported by libbpf.\n");
+ pr_warn("Error: shared umems not supported by libbpf.\n");
return -EBUSY;
}
@@ -550,8 +637,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
}
}
- optlen = sizeof(off);
- err = getsockopt(xsk->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);
+ err = xsk_get_mmap_offsets(xsk->fd, &off);
if (err) {
err = -errno;
goto out_socket;
@@ -637,7 +723,6 @@ out_xsk_alloc:
int xsk_umem__delete(struct xsk_umem *umem)
{
struct xdp_mmap_offsets off;
- socklen_t optlen;
int err;
if (!umem)
@@ -646,8 +731,7 @@ int xsk_umem__delete(struct xsk_umem *umem)
if (umem->refcount)
return -EBUSY;
- optlen = sizeof(off);
- err = getsockopt(umem->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);
+ err = xsk_get_mmap_offsets(umem->fd, &off);
if (!err) {
munmap(umem->fill->ring - off.fr.desc,
off.fr.desc + umem->config.fill_size * sizeof(__u64));
@@ -665,7 +749,6 @@ void xsk_socket__delete(struct xsk_socket *xsk)
{
size_t desc_sz = sizeof(struct xdp_desc);
struct xdp_mmap_offsets off;
- socklen_t optlen;
int err;
if (!xsk)
@@ -676,8 +759,7 @@ void xsk_socket__delete(struct xsk_socket *xsk)
close(xsk->prog_fd);
}
- optlen = sizeof(off);
- err = getsockopt(xsk->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);
+ err = xsk_get_mmap_offsets(xsk->fd, &off);
if (!err) {
if (xsk->rx) {
munmap(xsk->rx->ring - off.rx.desc,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.