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Message-Id: <20190430124536.7734-3-bjorn.topel@gmail.com>
Date: Tue, 30 Apr 2019 14:45:36 +0200
From: Björn Töpel <bjorn.topel@...il.com>
To: ast@...nel.org, daniel@...earbox.net, netdev@...r.kernel.org
Cc: Björn Töpel <bjorn.topel@...el.com>,
magnus.karlsson@...el.com, magnus.karlsson@...il.com,
bpf@...r.kernel.org, u9012063@...il.com
Subject: [PATCH bpf 2/2] libbpf: proper XSKMAP cleanup
From: Björn Töpel <bjorn.topel@...el.com>
The bpf_map_update_elem() function, when used on an XSKMAP, will fail
if not a valid AF_XDP socket is passed as value. Therefore, this is
function cannot be used to clear the XSKMAP. Instead, the
bpf_map_delete_elem() function should be used for that.
This patch also simplifies the code by breaking up
xsk_update_bpf_maps() into three smaller functions.
Reported-by: William Tu <u9012063@...il.com>
Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets")
Signed-off-by: Björn Töpel <bjorn.topel@...el.com>
---
tools/lib/bpf/xsk.c | 115 +++++++++++++++++++++++---------------------
1 file changed, 60 insertions(+), 55 deletions(-)
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index af5f310ecca1..c2e6da464504 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -386,21 +386,17 @@ static void xsk_delete_bpf_maps(struct xsk_socket *xsk)
{
close(xsk->qidconf_map_fd);
close(xsk->xsks_map_fd);
+ xsk->qidconf_map_fd = -1;
+ xsk->xsks_map_fd = -1;
}
-static int xsk_update_bpf_maps(struct xsk_socket *xsk, int qidconf_value,
- int xsks_value)
+static int xsk_lookup_bpf_maps(struct xsk_socket *xsk)
{
- bool qidconf_map_updated = false, xsks_map_updated = false;
+ __u32 i, *map_ids, num_maps, prog_len = sizeof(struct bpf_prog_info);
+ __u32 map_len = sizeof(struct bpf_map_info);
struct bpf_prog_info prog_info = {};
- __u32 prog_len = sizeof(prog_info);
struct bpf_map_info map_info;
- __u32 map_len = sizeof(map_info);
- __u32 *map_ids;
- int reset_value = 0;
- __u32 num_maps;
- unsigned int i;
- int err;
+ int fd, err;
err = bpf_obj_get_info_by_fd(xsk->prog_fd, &prog_info, &prog_len);
if (err)
@@ -421,66 +417,71 @@ static int xsk_update_bpf_maps(struct xsk_socket *xsk, int qidconf_value,
goto out_map_ids;
for (i = 0; i < prog_info.nr_map_ids; i++) {
- int fd;
+ if (xsk->qidconf_map_fd != -1 && xsk->xsks_map_fd != -1)
+ break;
fd = bpf_map_get_fd_by_id(map_ids[i]);
- if (fd < 0) {
- err = -errno;
- goto out_maps;
- }
+ if (fd < 0)
+ continue;
err = bpf_obj_get_info_by_fd(fd, &map_info, &map_len);
- if (err)
- goto out_maps;
+ if (err) {
+ close(fd);
+ continue;
+ }
if (!strcmp(map_info.name, "qidconf_map")) {
- err = bpf_map_update_elem(fd, &xsk->queue_id,
- &qidconf_value, 0);
- if (err)
- goto out_maps;
- qidconf_map_updated = true;
xsk->qidconf_map_fd = fd;
- } else if (!strcmp(map_info.name, "xsks_map")) {
- err = bpf_map_update_elem(fd, &xsk->queue_id,
- &xsks_value, 0);
- if (err)
- goto out_maps;
- xsks_map_updated = true;
+ continue;
+ }
+
+ if (!strcmp(map_info.name, "xsks_map")) {
xsk->xsks_map_fd = fd;
+ continue;
}
- if (qidconf_map_updated && xsks_map_updated)
- break;
+ close(fd);
}
- if (!(qidconf_map_updated && xsks_map_updated)) {
+ err = 0;
+ if (xsk->qidconf_map_fd < 0 || xsk->xsks_map_fd < 0) {
err = -ENOENT;
- goto out_maps;
+ xsk_delete_bpf_maps(xsk);
}
- err = 0;
- goto out_success;
-
-out_maps:
- if (qidconf_map_updated)
- (void)bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id,
- &reset_value, 0);
- if (xsks_map_updated)
- (void)bpf_map_update_elem(xsk->xsks_map_fd, &xsk->queue_id,
- &reset_value, 0);
-out_success:
- if (qidconf_map_updated)
- close(xsk->qidconf_map_fd);
- if (xsks_map_updated)
- close(xsk->xsks_map_fd);
out_map_ids:
free(map_ids);
return err;
}
+static void xsk_clear_bpf_maps(struct xsk_socket *xsk)
+{
+ int qid = false;
+
+ (void)bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id, &qid, 0);
+ (void)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;
+}
+
static int xsk_setup_xdp_prog(struct xsk_socket *xsk)
{
- bool prog_attached = false;
__u32 prog_id = 0;
int err;
@@ -490,7 +491,6 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk)
return err;
if (!prog_id) {
- prog_attached = true;
err = xsk_create_bpf_maps(xsk);
if (err)
return err;
@@ -500,20 +500,21 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk)
goto out_maps;
} else {
xsk->prog_fd = bpf_prog_get_fd_by_id(prog_id);
+ err = xsk_lookup_bpf_maps(xsk);
+ if (err)
+ goto out_load;
}
- err = xsk_update_bpf_maps(xsk, true, xsk->fd);
+ err = xsk_set_bpf_maps(xsk);
if (err)
goto out_load;
return 0;
out_load:
- if (prog_attached)
- close(xsk->prog_fd);
+ close(xsk->prog_fd);
out_maps:
- if (prog_attached)
- xsk_delete_bpf_maps(xsk);
+ xsk_delete_bpf_maps(xsk);
return err;
}
@@ -641,6 +642,9 @@ 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;
+
if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) {
err = xsk_setup_xdp_prog(xsk);
if (err)
@@ -705,7 +709,8 @@ void xsk_socket__delete(struct xsk_socket *xsk)
if (!xsk)
return;
- (void)xsk_update_bpf_maps(xsk, 0, 0);
+ xsk_clear_bpf_maps(xsk);
+ xsk_delete_bpf_maps(xsk);
optlen = sizeof(off);
err = getsockopt(xsk->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);
--
2.20.1
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