netlink: refactor error numbers from netlink

Originally, these were error numbers from libnl3. These error numbers
are separate from errno, which is unfortunate, because sometimes we
care about the native errno returned from kernel.

Now, refactor them so that the error numbers are in the shared realm
of errno, but failures from kernel or underlying API are still returned
via their native errno.

- NLE_INVAL doesn't exist anymore. Passing invalid arguments to a function
  is commonly a bug. g_return_*(NLE_BUG) is the right answer to that.

- NLE_NOMEM and NLE_AGAIN is replaced by their errno counterparts.

- drop several error numbers. If nobody cares about these numbers,
  there is no reason to have a specific error number for them.
  NLE_UNSPEC is sufficient.

src/platform/nm-linux-platform.c

@@ -80,10 +80,6 @@ enum {
 
 #define VLAN_FLAG_MVRP 0x8
 
-/* nm-internal error codes for libnl. Make sure they don't overlap. */
-#define _NLE_NM_NOBUFS 500
-#define _NLE_MSG_TRUNC 501
-
 /*****************************************************************************/
 
 #define IFQDISCSIZ                      32
@@ -6496,19 +6492,19 @@ continue_reading:
 			if (!handle_events)
 				goto continue_reading;
 		}
-		n = -_NLE_MSG_TRUNC;
+		n = -NLE_USER_MSG_TRUNC;
 		break;
 	}
 	case -ENOBUFS:
-		n = -_NLE_NM_NOBUFS;
+		n = -NLE_USER_NOBUFS;
 		break;
-	case -NLE_NOMEM:
+	case -ENOMEM:
 		if (errno == ENOBUFS) {
 			/* we are very much interested in a overrun of the receive buffer.
-			 * nl_recv() maps all kinds of errors to NLE_NOMEM, so check also
+			 * nl_recv() maps all kinds of errors to ENOMEM, so check also
 			 * for errno explicitly. And if so, hack our own return code to signal
 			 * the overrun. */
-			n = -_NLE_NM_NOBUFS;
+			n = -NLE_USER_NOBUFS;
 		}
 		break;
 	}
@@ -6526,7 +6522,7 @@ continue_reading:
 
 		msg = nlmsg_convert (hdr);
 		if (!msg) {
-			err = -NLE_NOMEM;
+			err = -ENOMEM;
 			goto out;
 		}
 
@@ -6686,19 +6682,19 @@ event_handler_read_netlink (NMPlatform *platform, gboolean wait_for_acks)
 
 			if (nle < 0) {
 				switch (nle) {
-				case -NLE_AGAIN:
+				case -EAGAIN:
 					goto after_read;
 				case -NLE_DUMP_INTR:
 					_LOGD ("netlink: read: uncritical failure to retrieve incoming events: %s (%d)", nl_geterror (nle), nle);
 					break;
-				case -_NLE_MSG_TRUNC:
+				case -NLE_USER_MSG_TRUNC:
-				case -_NLE_NM_NOBUFS:
+				case -NLE_USER_NOBUFS:
 					_LOGI ("netlink: read: %s. Need to resynchronize platform cache",
 					       ({
 					            const char *_reason = "unknown";
 					            switch (nle) {
-					            case -_NLE_MSG_TRUNC: _reason = "message truncated";       break;
+					            case -NLE_USER_MSG_TRUNC: _reason = "message truncated";       break;
-					            case -_NLE_NM_NOBUFS: _reason = "too many netlink events"; break;
+					            case -NLE_USER_NOBUFS: _reason = "too many netlink events"; break;
 					            }
 					            _reason;
 					       }));

src/platform/nm-netlink.c

@@ -65,6 +65,40 @@ struct nl_sock {
 
 /*****************************************************************************/
 
+NM_UTILS_LOOKUP_STR_DEFINE_STATIC (_geterror, int,
+	NM_UTILS_LOOKUP_DEFAULT (NULL),
+	NM_UTILS_LOOKUP_ITEM (NLE_UNSPEC,          "NLE_UNSPEC"),
+	NM_UTILS_LOOKUP_ITEM (NLE_BUG,             "NLE_BUG"),
+	NM_UTILS_LOOKUP_ITEM (NLE_NATIVE_ERRNO,    "NLE_NATIVE_ERRNO"),
+
+	NM_UTILS_LOOKUP_ITEM (NLE_ATTRSIZE,        "NLE_ATTRSIZE"),
+	NM_UTILS_LOOKUP_ITEM (NLE_BAD_SOCK,        "NLE_BAD_SOCK"),
+	NM_UTILS_LOOKUP_ITEM (NLE_DUMP_INTR,       "NLE_DUMP_INTR"),
+	NM_UTILS_LOOKUP_ITEM (NLE_MSG_OVERFLOW,    "NLE_MSG_OVERFLOW"),
+	NM_UTILS_LOOKUP_ITEM (NLE_MSG_TOOSHORT,    "NLE_MSG_TOOSHORT"),
+	NM_UTILS_LOOKUP_ITEM (NLE_MSG_TRUNC,       "NLE_MSG_TRUNC"),
+	NM_UTILS_LOOKUP_ITEM (NLE_SEQ_MISMATCH,    "NLE_SEQ_MISMATCH"),
+	NM_UTILS_LOOKUP_ITEM (NLE_USER_NOBUFS,     "NLE_USER_NOBUFS"),
+	NM_UTILS_LOOKUP_ITEM (NLE_USER_MSG_TRUNC,  "NLE_USER_MSG_TRUNC"),
+)
+
+const char *
+nl_geterror (int err)
+{
+	const char *s;
+
+	err = nl_errno (err);
+
+	if (err >= _NLE_BASE) {
+		s = _geterror (err);
+		if (s)
+			return s;
+	}
+	return g_strerror (err);
+}
+
+/*****************************************************************************/
+
 NM_UTILS_ENUM2STR_DEFINE (nl_nlmsgtype2str, int,
 	NM_UTILS_ENUM2STR (NLMSG_NOOP,    "NOOP"),
 	NM_UTILS_ENUM2STR (NLMSG_ERROR,   "ERROR"),
@@ -365,7 +399,7 @@ nlmsg_append (struct nl_msg *n, void *data, size_t len, int pad)
 
 	tmp = nlmsg_reserve(n, len, pad);
 	if (tmp == NULL)
-		return -NLE_NOMEM;
+		return -ENOMEM;
 
 	memcpy(tmp, data, len);
 	return 0;
@@ -456,9 +490,9 @@ nla_put (struct nl_msg *msg, int attrtype, int datalen, const void *data)
 	nla = nla_reserve(msg, attrtype, datalen);
 	if (!nla) {
 		if (datalen < 0)
-			return -NLE_INVAL;
+			g_return_val_if_reached (-NLE_BUG);
 
-		return -NLE_NOMEM;
+		return -ENOMEM;
 	}
 
 	if (datalen > 0)
@@ -579,15 +613,15 @@ validate_nla (const struct nlattr *nla, int maxtype,
 		minlen = nla_attr_minlen[pt->type];
 
 	if (nla_len(nla) < minlen)
-		return -NLE_RANGE;
+		return -NLE_UNSPEC;
 
 	if (pt->maxlen && nla_len(nla) > pt->maxlen)
-		return -NLE_RANGE;
+		return -NLE_UNSPEC;
 
 	if (pt->type == NLA_STRING) {
 		const char *data = nla_data(nla);
 		if (data[nla_len(nla) - 1] != '\0')
-			return -NLE_INVAL;
+			return -NLE_UNSPEC;
 	}
 
 	return 0;
@@ -876,7 +910,7 @@ nl_cb_err (struct nl_cb *cb, enum nl_cb_kind kind,
            nl_recvmsg_err_cb_t func, void *arg)
 {
 	if ((unsigned int) kind > NL_CB_KIND_MAX)
-		return -NLE_RANGE;
+		g_return_val_if_reached (-NLE_BUG);
 
 	if (kind == NL_CB_CUSTOM) {
 		cb->cb_err = func;
@@ -894,10 +928,10 @@ nl_cb_set (struct nl_cb *cb, enum nl_cb_type type, enum nl_cb_kind kind,
            nl_recvmsg_msg_cb_t func, void *arg)
 {
 	if ((unsigned int) type > NL_CB_TYPE_MAX)
-		return -NLE_RANGE;
+		g_return_val_if_reached (-NLE_BUG);
 
 	if ((unsigned int) kind > NL_CB_KIND_MAX)
-		return -NLE_RANGE;
+		g_return_val_if_reached (-NLE_BUG);
 
 	if (kind == NL_CB_CUSTOM) {
 		cb->cb_set[type] = func;
@@ -993,10 +1027,10 @@ nl_socket_set_passcred (struct nl_sock *sk, int state)
 	if (sk->s_fd == -1)
 		return -NLE_BAD_SOCK;
 
-	err = setsockopt(sk->s_fd, SOL_SOCKET, SO_PASSCRED,
+	err = setsockopt (sk->s_fd, SOL_SOCKET, SO_PASSCRED,
-			 &state, sizeof(state));
+	                  &state, sizeof(state));
 	if (err < 0)
-		return -errno;
+		return -nl_syserr2nlerr (errno);
 
 	if (state)
 		sk->s_flags |= NL_SOCK_PASSCRED;
@@ -1027,7 +1061,7 @@ nl_socket_set_nonblocking (const struct nl_sock *sk)
 		return -NLE_BAD_SOCK;
 
 	if (fcntl(sk->s_fd, F_SETFL, O_NONBLOCK) < 0)
-		return -errno;
+		return -nl_syserr2nlerr (errno);
 
 	return 0;
 }
@@ -1049,13 +1083,13 @@ nl_socket_set_buffer_size (struct nl_sock *sk, int rxbuf, int txbuf)
 	err = setsockopt (sk->s_fd, SOL_SOCKET, SO_SNDBUF,
 	                  &txbuf, sizeof(txbuf));
 	if (err < 0) {
-		return -errno;
+		return -nl_syserr2nlerr (errno);
 	}
 
 	err = setsockopt (sk->s_fd, SOL_SOCKET, SO_RCVBUF,
 	                  &rxbuf, sizeof(rxbuf));
 	if (err < 0) {
-		return -errno;
+		return -nl_syserr2nlerr (errno);
 	}
 
 	return 0;
@@ -1075,14 +1109,14 @@ nl_socket_add_memberships (struct nl_sock *sk, int group, ...)
 	while (group != 0) {
 		if (group < 0) {
 			va_end(ap);
-			return -NLE_INVAL;
+			g_return_val_if_reached (-NLE_BUG);
 		}
 
 		err = setsockopt (sk->s_fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
 		                  &group, sizeof(group));
 		if (err < 0) {
 			va_end(ap);
-			return -errno;
+			return -nl_syserr2nlerr (errno);
 		}
 
 		group = va_arg(ap, int);
@@ -1111,7 +1145,7 @@ nl_connect (struct nl_sock *sk, int protocol)
 
 	sk->s_fd = socket (AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
 	if (sk->s_fd < 0) {
-		err = -errno;
+		err = -nl_syserr2nlerr (errno);
 		goto errout;
 	}
 
@@ -1124,7 +1158,7 @@ nl_connect (struct nl_sock *sk, int protocol)
 	err = bind (sk->s_fd, (struct sockaddr*) &sk->s_local,
 	            sizeof(sk->s_local));
 	if (err != 0) {
-		err = -errno;
+		err = -nl_syserr2nlerr (errno);
 		goto errout;
 	}
 
@@ -1132,17 +1166,17 @@ nl_connect (struct nl_sock *sk, int protocol)
 	err = getsockname (sk->s_fd, (struct sockaddr *) &local,
 	                   &addrlen);
 	if (err < 0) {
-		err = -errno;
+		err = -nl_syserr2nlerr (errno);
 		goto errout;
 	}
 
 	if (addrlen != sizeof(local)) {
-		err = -NLE_NOADDR;
+		err = -NLE_UNSPEC;
 		goto errout;
 	}
 
 	if (local.nl_family != AF_NETLINK) {
-		err = -NLE_AF_NOSUPPORT;
+		err = -NLE_UNSPEC;
 		goto errout;
 	}
 
@@ -1150,12 +1184,12 @@ nl_connect (struct nl_sock *sk, int protocol)
 	sk->s_proto = protocol;
 
 	return 0;
+
 errout:
 	if (sk->s_fd != -1) {
 		close(sk->s_fd);
 		sk->s_fd = -1;
 	}
-
 	return err;
 }
 
@@ -1174,7 +1208,7 @@ nl_wait_for_ack(struct nl_sock *sk)
 
 	cb = nl_cb_clone(sk->s_cb);
 	if (cb == NULL)
-		return -NLE_NOMEM;
+		return -ENOMEM;
 
 	nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_wait_handler, NULL);
 	err = nl_recvmsgs(sk, cb);
@@ -1229,7 +1263,7 @@ continue_reading:
 		nlmsg_free(msg);
 		msg = nlmsg_convert(hdr);
 		if (!msg) {
-			err = -NLE_NOMEM;
+			err = -ENOMEM;
 			goto out;
 		}
 
@@ -1441,7 +1475,7 @@ nl_sendmsg (struct nl_sock *sk, struct nl_msg *msg, struct msghdr *hdr)
 
 	ret = sendmsg(sk->s_fd, hdr, 0);
 	if (ret < 0)
-		return -errno;
+		return -nl_syserr2nlerr (errno);
 
 	return ret;
 }
@@ -1547,7 +1581,7 @@ nl_recv (struct nl_sock *sk, struct sockaddr_nl *nla,
 	int retval = 0;
 
 	if (!buf || !nla)
-		return -NLE_INVAL;
+		g_return_val_if_reached (-NLE_BUG);
 
 	if (   (sk->s_flags & NL_MSG_PEEK)
 	    || (!(sk->s_flags & NL_MSG_PEEK_EXPLICIT) && sk->s_bufsize == 0))
@@ -1560,7 +1594,7 @@ nl_recv (struct nl_sock *sk, struct sockaddr_nl *nla,
 	iov.iov_base = malloc(iov.iov_len);
 
 	if (!iov.iov_base) {
-		retval = -NLE_NOMEM;
+		retval = -ENOMEM;
 		goto abort;
 	}
 
@@ -1568,7 +1602,7 @@ nl_recv (struct nl_sock *sk, struct sockaddr_nl *nla,
 		msg.msg_controllen = CMSG_SPACE(sizeof(struct ucred));
 		msg.msg_control = malloc(msg.msg_controllen);
 		if (!msg.msg_control) {
-			retval = -NLE_NOMEM;
+			retval = -ENOMEM;
 			goto abort;
 		}
 	}
@@ -1583,7 +1617,7 @@ retry:
 		if (errno == EINTR)
 			goto retry;
 
-		retval = -errno;
+		retval = -nl_syserr2nlerr (errno);
 		goto abort;
 	}
 
@@ -1598,7 +1632,7 @@ retry:
 		msg.msg_controllen *= 2;
 		tmp = realloc(msg.msg_control, msg.msg_controllen);
 		if (!tmp) {
-			retval = -NLE_NOMEM;
+			retval = -ENOMEM;
 			goto abort;
 		}
 		msg.msg_control = tmp;
@@ -1620,7 +1654,7 @@ retry:
 		iov.iov_len = n;
 		tmp = realloc(iov.iov_base, iov.iov_len);
 		if (!tmp) {
-			retval = -NLE_NOMEM;
+			retval = -ENOMEM;
 			goto abort;
 		}
 		iov.iov_base = tmp;
@@ -1635,7 +1669,7 @@ retry:
 	}
 
 	if (msg.msg_namelen != sizeof(struct sockaddr_nl)) {
-		retval =  -NLE_NOADDR;
+		retval =  -NLE_UNSPEC;
 		goto abort;
 	}
 
@@ -1649,7 +1683,7 @@ retry:
 				continue;
 			tmpcreds = malloc(sizeof(*tmpcreds));
 			if (!tmpcreds) {
-				retval = -NLE_NOMEM;
+				retval = -ENOMEM;
 				goto abort;
 			}
 			memcpy(tmpcreds, CMSG_DATA(cmsg), sizeof(*tmpcreds));

src/platform/nm-netlink.h

@@ -27,44 +27,54 @@
 
 /*****************************************************************************/
 
-#define NLE_AGAIN               EAGAIN
+#define _NLE_BASE               100000
-#define NLE_NOMEM               ENOMEM
+#define NLE_UNSPEC              (_NLE_BASE +  0)
-#define NLE_BAD_SOCK            EBADF
+#define NLE_BUG                 (_NLE_BASE +  1)
-#define NLE_INVAL               EINVAL
+#define NLE_NATIVE_ERRNO        (_NLE_BASE +  2)
-#define NLE_RANGE               ERANGE
+#define NLE_SEQ_MISMATCH        (_NLE_BASE +  3)
-#define NLE_OBJ_NOTFOUND        ENOENT
+#define NLE_MSG_TRUNC           (_NLE_BASE +  4)
-#define NLE_NOADDR              EADDRNOTAVAIL
+#define NLE_MSG_TOOSHORT        (_NLE_BASE +  5)
-#define NLE_MSG_OVERFLOW        EOVERFLOW
+#define NLE_DUMP_INTR           (_NLE_BASE +  6)
-#define NLE_AF_NOSUPPORT        EAFNOSUPPORT
+#define NLE_ATTRSIZE            (_NLE_BASE +  7)
+#define NLE_BAD_SOCK            (_NLE_BASE +  8)
+#define NLE_NOADDR              (_NLE_BASE + 12)
+#define NLE_MSG_OVERFLOW        (_NLE_BASE + 13)
 
-#define NLE_SEQ_MISMATCH        10016
+/* user errors, these errors are never returned by netlink functions themself,
-#define NLE_MSG_TRUNC           10018
+ * but are reserved for other components. */
-#define NLE_MSG_TOOSHORT        10021
+#define NLE_USER_NOBUFS         (_NLE_BASE + 15)
-#define NLE_DUMP_INTR           10033
+#define NLE_USER_MSG_TRUNC      (_NLE_BASE + 16)
-#define NLE_ATTRSIZE            10034
+
-#define NLE_BUG                 19000
+#define _NLE_BASE_END           (_NLE_BASE + 17)
 
 static inline int
-nl_errno (int error)
+nl_errno (int err)
 {
-	/* the error codes from our netlink implementation are plain errno.
+	/* the error codes from our netlink implementation are plain errno
-	 * However, often we encode them as negative values.
+	 * extended with our own error in a particular range starting from
+	 * _NLE_BASE.
 	 *
-	 * A negative errno is the same as it's positive counterpart.
+	 * However, often we encode errors as negative values. This function
-	 *
+	 * normalizes the error and returns it's positive value. */
-	 * This function normalizes the error code and always returns a
+	return err >= 0
-	 * non-negative value. */
+	       ? err
-	return error >= 0
+	       : ((err == G_MININT) ? NLE_BUG : -errno);
-	       ? error
-	       : ((error == G_MININT) ? NLE_BUG : -errno);
 }
 
-static inline const char *
+static inline int
-nl_geterror (int error)
+nl_syserr2nlerr (int err)
 {
-	return g_strerror (nl_errno (error));
+	if (err == G_MININT)
+		return NLE_NATIVE_ERRNO;
+	if (err < 0)
+		err = -err;
+	return (err >= _NLE_BASE && err < _NLE_BASE_END)
+	       ? NLE_NATIVE_ERRNO
+	       : err;
 }
 
+const char *nl_geterror (int err);
+
 /*****************************************************************************/
 
 /* Basic attribute data types */

src/platform/wifi/wifi-utils-nl80211.c

@@ -82,7 +82,7 @@ genl_ctrl_resolve (struct nl_sock *sk, const char *name)
 	struct nl_msg *msg;
 	struct nl_cb *cb, *orig;
 	int rc;
-	int result = -NLE_OBJ_NOTFOUND;
+	int result = -ENOENT;
 	gint32 response_data = -1;
 
 	if (!(orig = nl_socket_get_cb (sk)))
@@ -235,7 +235,7 @@ _nl80211_send_and_recv (struct nl_sock *nl_sock,
 	 */
 	while (!done) {
 		err = nl_recvmsgs (nl_sock, cb);
-		if (err && err != -NLE_AGAIN) {
+		if (err < 0 && err != -EAGAIN) {
 			/* Kernel scan list can change while we are dumping it, as new scan
 			 * results from H/W can arrive. BSS info is assured to be consistent
 			 * and we don't need consistent view of whole scan list. Hence do