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libbpf: remove qidconf and better support external bpf programs. 

Use the recent change to XSKMAP bpf_map_lookup_elem() to test if
there is a xsk present in the map instead of duplicating the work
with qidconf.

Fix things so callers using XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD
bypass any internal bpf maps, so xsk_socket__{create|delete} works
properly.

Clean up error handling path.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jonathan Lemon 2019-06-06 13:59:43 -07:00 committed by Alexei Starovoitov
parent 940e7be34a
commit 10a13bb40e
1 changed files with 28 additions and 75 deletions
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103
tools/lib/bpf/xsk.c
View File

@ -60,10 +60,8 @@ struct xsk_socket {
struct xsk_umem *umem;
struct xsk_socket_config config;
int fd;
int xsks_map;
int ifindex;
int prog_fd;
int qidconf_map_fd;
int xsks_map_fd;
__u32 queue_id;
char ifname[IFNAMSIZ];
@ -265,15 +263,11 @@ 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 *qidconf, index = ctx->rx_queue_index;
* int index = ctx->rx_queue_index;
*
* // A set entry here means that the correspnding queue_id
* // has an active AF_XDP socket bound to it.
* qidconf = bpf_map_lookup_elem(&qidconf_map, &index);
* if (!qidconf)
* return XDP_ABORTED;
*
* if (*qidconf)
* if (bpf_map_lookup_elem(&xsks_map, &index))
* return bpf_redirect_map(&xsks_map, index, 0);
*
* return XDP_PASS;
@ -286,15 +280,10 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk)
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_1, -4),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),
BPF_LD_MAP_FD(BPF_REG_1, xsk->qidconf_map_fd),
BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_MOV32_IMM(BPF_REG_0, 0),
/* if r1 == 0 goto +8 */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 8),
BPF_MOV32_IMM(BPF_REG_0, 2),
/* r1 = *(u32 *)(r1 + 0) */
BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1, 0),
/* if r1 == 0 goto +5 */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 5),
/* r2 = *(u32 *)(r10 - 4) */
@ -366,18 +355,11 @@ static int xsk_create_bpf_maps(struct xsk_socket *xsk)
if (max_queues < 0)
return max_queues;
fd = bpf_create_map_name(BPF_MAP_TYPE_ARRAY, "qidconf_map",
fd = bpf_create_map_name(BPF_MAP_TYPE_XSKMAP, "xsks_map",
sizeof(int), sizeof(int), max_queues, 0);
if (fd < 0)
return fd;
xsk->qidconf_map_fd = fd;
fd = bpf_create_map_name(BPF_MAP_TYPE_XSKMAP, "xsks_map",
sizeof(int), sizeof(int), max_queues, 0);
if (fd < 0) {
close(xsk->qidconf_map_fd);
return fd;
}
xsk->xsks_map_fd = fd;
return 0;
@ -385,10 +367,8 @@ static int xsk_create_bpf_maps(struct xsk_socket *xsk)
static void xsk_delete_bpf_maps(struct xsk_socket *xsk)
{
close(xsk->qidconf_map_fd);
bpf_map_delete_elem(xsk->xsks_map_fd, &xsk->queue_id);
close(xsk->xsks_map_fd);
xsk->qidconf_map_fd = -1;
xsk->xsks_map_fd = -1;
}
static int xsk_lookup_bpf_maps(struct xsk_socket *xsk)
@ -417,10 +397,9 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk)
if (err)
goto out_map_ids;
for (i = 0; i < prog_info.nr_map_ids; i++) {
if (xsk->qidconf_map_fd != -1 && xsk->xsks_map_fd != -1)
break;
xsk->xsks_map_fd = -1;
for (i = 0; i < prog_info.nr_map_ids; i++) {
fd = bpf_map_get_fd_by_id(map_ids[i]);
if (fd < 0)
continue;
@ -431,11 +410,6 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk)
continue;
}
if (!strcmp(map_info.name, "qidconf_map")) {
xsk->qidconf_map_fd = fd;
continue;
}
if (!strcmp(map_info.name, "xsks_map")) {
xsk->xsks_map_fd = fd;
continue;
@ -445,40 +419,18 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk)
}
err = 0;
if (xsk->qidconf_map_fd < 0 || xsk->xsks_map_fd < 0) {
if (xsk->xsks_map_fd == -1)
err = -ENOENT;
xsk_delete_bpf_maps(xsk);
}
out_map_ids:
free(map_ids);
return err;
}
static void xsk_clear_bpf_maps(struct xsk_socket *xsk)
{
int qid = false;
bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id, &qid, 0);
bpf_map_delete_elem(xsk->xsks_map_fd, &xsk->queue_id);
}
static int xsk_set_bpf_maps(struct xsk_socket *xsk)
{
int qid = true, fd = xsk->fd, err;
err = bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id, &qid, 0);
if (err)
goto out;
err = bpf_map_update_elem(xsk->xsks_map_fd, &xsk->queue_id, &fd, 0);
if (err)
goto out;
return 0;
out:
xsk_clear_bpf_maps(xsk);
return err;
return bpf_map_update_elem(xsk->xsks_map_fd, &xsk->queue_id,
&xsk->fd, 0);
}
static int xsk_setup_xdp_prog(struct xsk_socket *xsk)
@ -497,26 +449,27 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk)
return err;
err = xsk_load_xdp_prog(xsk);
if (err)
goto out_maps;
if (err) {
xsk_delete_bpf_maps(xsk);
return err;
}
} else {
xsk->prog_fd = bpf_prog_get_fd_by_id(prog_id);
err = xsk_lookup_bpf_maps(xsk);
if (err)
goto out_load;
if (err) {
close(xsk->prog_fd);
return err;
}
}
err = xsk_set_bpf_maps(xsk);
if (err)
goto out_load;
if (err) {
xsk_delete_bpf_maps(xsk);
close(xsk->prog_fd);
return err;
}
return 0;
out_load:
close(xsk->prog_fd);
out_maps:
xsk_delete_bpf_maps(xsk);
return err;
}
int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
@ -643,9 +596,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
goto out_mmap_tx;
}
xsk->qidconf_map_fd = -1;
xsk->xsks_map_fd = -1;
xsk->prog_fd = -1;
if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) {
err = xsk_setup_xdp_prog(xsk);
if (err)
@ -708,8 +659,10 @@ void xsk_socket__delete(struct xsk_socket *xsk)
if (!xsk)
return;
xsk_clear_bpf_maps(xsk);
xsk_delete_bpf_maps(xsk);
if (xsk->prog_fd != -1) {
xsk_delete_bpf_maps(xsk);
close(xsk->prog_fd);
}
optlen = sizeof(off);
err = getsockopt(xsk->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);