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Diffstat (limited to 'iw.c')
-rw-r--r--iw.c127
1 files changed, 106 insertions, 21 deletions
diff --git a/iw.c b/iw.c
index dc99566..35308ba 100644
--- a/iw.c
+++ b/iw.c
@@ -13,6 +13,7 @@
#include <fcntl.h>
#include <unistd.h>
#include <stdbool.h>
+#include <linux/netlink.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/family.h>
@@ -54,14 +55,19 @@ static int nl80211_init(struct nl80211_state *state)
return -ENOMEM;
}
- nl_socket_set_buffer_size(state->nl_sock, 8192, 8192);
-
if (genl_connect(state->nl_sock)) {
fprintf(stderr, "Failed to connect to generic netlink.\n");
err = -ENOLINK;
goto out_handle_destroy;
}
+ nl_socket_set_buffer_size(state->nl_sock, 8192, 8192);
+
+ /* try to set NETLINK_EXT_ACK to 1, ignoring errors */
+ err = 1;
+ setsockopt(nl_socket_get_fd(state->nl_sock), SOL_NETLINK,
+ NETLINK_EXT_ACK, &err, sizeof(err));
+
state->nl80211_id = genl_ctrl_resolve(state->nl_sock, "nl80211");
if (state->nl80211_id < 0) {
fprintf(stderr, "nl80211 not found.\n");
@@ -83,12 +89,12 @@ static void nl80211_cleanup(struct nl80211_state *state)
static int cmd_size;
-extern struct cmd __start___cmd;
-extern struct cmd __stop___cmd;
+extern struct cmd *__start___cmd[];
+extern struct cmd *__stop___cmd;
-#define for_each_cmd(_cmd) \
- for (_cmd = &__start___cmd; _cmd < &__stop___cmd; \
- _cmd = (const struct cmd *)((char *)_cmd + cmd_size))
+#define for_each_cmd(_cmd, i) \
+ for (i = 0; i < &__stop___cmd - __start___cmd; i++) \
+ if ((_cmd = __start___cmd[i]))
static void __usage_cmd(const struct cmd *cmd, char *indent, bool full)
@@ -186,6 +192,7 @@ static void usage(int argc, char **argv)
bool full = argc >= 0;
const char *sect_filt = NULL;
const char *cmd_filt = NULL;
+ unsigned int i, j;
if (argc > 0)
sect_filt = argv[0];
@@ -197,7 +204,7 @@ static void usage(int argc, char **argv)
usage_options();
printf("\t--version\tshow version (%s)\n", iw_version);
printf("Commands:\n");
- for_each_cmd(section) {
+ for_each_cmd(section, i) {
if (section->parent)
continue;
@@ -207,7 +214,7 @@ static void usage(int argc, char **argv)
if (section->handler && !section->hidden)
__usage_cmd(section, "\t", full);
- for_each_cmd(cmd) {
+ for_each_cmd(cmd, j) {
if (section != cmd->parent)
continue;
if (!cmd->handler || cmd->hidden)
@@ -228,7 +235,6 @@ static void usage(int argc, char **argv)
}
static int print_help(struct nl80211_state *state,
- struct nl_cb *cb,
struct nl_msg *msg,
int argc, char **argv,
enum id_input id)
@@ -274,8 +280,47 @@ static int phy_lookup(char *name)
static int error_handler(struct sockaddr_nl *nla, struct nlmsgerr *err,
void *arg)
{
+ struct nlmsghdr *nlh = (struct nlmsghdr *)err - 1;
+ int len = nlh->nlmsg_len;
+ struct nlattr *attrs;
+ struct nlattr *tb[NLMSGERR_ATTR_MAX + 1];
int *ret = arg;
- *ret = err->error;
+ int ack_len = sizeof(*nlh) + sizeof(int) + sizeof(*nlh);
+
+ if (err->error > 0) {
+ /*
+ * This is illegal, per netlink(7), but not impossible (think
+ * "vendor commands"). Callers really expect negative error
+ * codes, so make that happen.
+ */
+ fprintf(stderr,
+ "ERROR: received positive netlink error code %d\n",
+ err->error);
+ *ret = -EPROTO;
+ } else {
+ *ret = err->error;
+ }
+
+ if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
+ return NL_STOP;
+
+ if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
+ ack_len += err->msg.nlmsg_len - sizeof(*nlh);
+
+ if (len <= ack_len)
+ return NL_STOP;
+
+ attrs = (void *)((unsigned char *)nlh + ack_len);
+ len -= ack_len;
+
+ nla_parse(tb, NLMSGERR_ATTR_MAX, attrs, len, NULL);
+ if (tb[NLMSGERR_ATTR_MSG]) {
+ len = strnlen((char *)nla_data(tb[NLMSGERR_ATTR_MSG]),
+ nla_len(tb[NLMSGERR_ATTR_MSG]));
+ fprintf(stderr, "kernel reports: %*s\n", len,
+ (char *)nla_data(tb[NLMSGERR_ATTR_MSG]));
+ }
+
return NL_STOP;
}
@@ -293,6 +338,23 @@ static int ack_handler(struct nl_msg *msg, void *arg)
return NL_STOP;
}
+static int (*registered_handler)(struct nl_msg *, void *);
+static void *registered_handler_data;
+
+void register_handler(int (*handler)(struct nl_msg *, void *), void *data)
+{
+ registered_handler = handler;
+ registered_handler_data = data;
+}
+
+int valid_handler(struct nl_msg *msg, void *arg)
+{
+ if (registered_handler)
+ return registered_handler(msg, registered_handler_data);
+
+ return NL_OK;
+}
+
static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
int argc, char **argv, const struct cmd **cmdout)
{
@@ -301,7 +363,7 @@ static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
struct nl_cb *s_cb;
struct nl_msg *msg;
signed long long devidx = 0;
- int err, o_argc;
+ int err, o_argc, i;
const char *command, *section;
char *tmp, **o_argv;
enum command_identify_by command_idby = CIB_NONE;
@@ -353,7 +415,7 @@ static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
argc--;
argv++;
- for_each_cmd(sectcmd) {
+ for_each_cmd(sectcmd, i) {
if (sectcmd->parent)
continue;
/* ok ... bit of a hack for the dupe 'info' section */
@@ -371,7 +433,7 @@ static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
if (argc > 0) {
command = *argv;
- for_each_cmd(cmd) {
+ for_each_cmd(cmd, i) {
if (!cmd->handler)
continue;
if (cmd->parent != sectcmd)
@@ -424,7 +486,7 @@ static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
if (!cmd->cmd) {
argc = o_argc;
argv = o_argv;
- return cmd->handler(state, NULL, NULL, argc, argv, idby);
+ return cmd->handler(state, NULL, argc, argv, idby);
}
msg = nlmsg_alloc();
@@ -438,7 +500,7 @@ static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
if (!cb || !s_cb) {
fprintf(stderr, "failed to allocate netlink callbacks\n");
err = 2;
- goto out_free_msg;
+ goto out;
}
genlmsg_put(msg, 0, 0, state->nl80211_id, 0,
@@ -458,7 +520,7 @@ static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
break;
}
- err = cmd->handler(state, cb, msg, argc, argv, idby);
+ err = cmd->handler(state, msg, argc, argv, idby);
if (err)
goto out;
@@ -473,12 +535,13 @@ static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
nl_cb_err(cb, NL_CB_CUSTOM, error_handler, &err);
nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, finish_handler, &err);
nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_handler, &err);
+ nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, valid_handler, NULL);
while (err > 0)
nl_recvmsgs(state->nl_sock, cb);
out:
nl_cb_put(cb);
- out_free_msg:
+ nl_cb_put(s_cb);
nlmsg_free(msg);
return err;
nla_put_failure:
@@ -492,6 +555,25 @@ int handle_cmd(struct nl80211_state *state, enum id_input idby,
return __handle_cmd(state, idby, argc, argv, NULL);
}
+/*
+ * Unfortunately, I don't know how densely the linker packs the struct cmd.
+ * For example, if you have a 72-byte struct cmd, the linker will pad each
+ * out to 96 bytes before putting them together in the section. There must
+ * be some algorithm, but I haven't found it yet.
+ *
+ * We used to calculate this by taking the (abs value of) the difference
+ * between __section_get and __section_set, but if LTO is enabled then this
+ * stops working because the entries of the "__cmd" section get rearranged
+ * freely by the compiler/linker.
+ *
+ * Fix this by using yet another "__sizer" section that only contains these
+ * two entries - then the (abs value of) the difference between them will
+ * be how they get packed and that can be used to iterate the __cmd section
+ * as well.
+ */
+static struct cmd sizer1 __attribute__((section("__sizer"))) = {};
+static struct cmd sizer2 __attribute__((section("__sizer"))) = {};
+
int main(int argc, char **argv)
{
struct nl80211_state nlstate;
@@ -499,7 +581,7 @@ int main(int argc, char **argv)
const struct cmd *cmd = NULL;
/* calculate command size including padding */
- cmd_size = abs((long)&__section_set - (long)&__section_get);
+ cmd_size = labs((long)&sizer2 - (long)&sizer1);
/* strip off self */
argc--;
argv0 = *argv++;
@@ -544,8 +626,9 @@ int main(int argc, char **argv)
err = __handle_cmd(&nlstate, II_WDEV, argc, argv, &cmd);
} else {
int idx;
- enum id_input idby = II_NONE;
+ enum id_input idby;
detect:
+ idby = II_NONE;
if ((idx = if_nametoindex(argv[0])) != 0)
idby = II_NETDEV;
else if ((idx = phy_lookup(argv[0])) >= 0)
@@ -553,11 +636,13 @@ int main(int argc, char **argv)
err = __handle_cmd(&nlstate, idby, argc, argv, &cmd);
}
- if (err == 1) {
+ if (err == HANDLER_RET_USAGE) {
if (cmd)
usage_cmd(cmd);
else
usage(0, NULL);
+ } else if (err == HANDLER_RET_DONE) {
+ err = 0;
} else if (err < 0)
fprintf(stderr, "command failed: %s (%d)\n", strerror(-err), err);
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-30 12:26:20 +0000