Subject: Re: [PATCH v2 iproute2 3/3] bridge: mst: Add get/set support for MST states

From: Stephen Hemminger <[email-masked]>
Date: Thu, 27 Jun 2024 09:56:43 -0700

Please resolve the following issue.

> +static int mst_set(int argc, char **argv)
> +{
> +	struct {
> +		struct nlmsghdr		n;
> +		struct ifinfomsg	ifi;
> +		char			buf[512];
> +	} req = {
> +		.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
> +		.n.nlmsg_flags = NLM_F_REQUEST,
> +		.n.nlmsg_type = RTM_SETLINK,
> +		.ifi.ifi_family = PF_BRIDGE,
> +	};
> +	char *d = NULL, *m = NULL, *s = NULL, *endptr;
> +	struct rtattr *af_spec, *mst, *entry;
> +	__u16 msti;
> +	__u8 state;
> +
> +	while (argc > 0) {
> +		if (strcmp(*argv, "dev") == 0) {
> +			NEXT_ARG();
> +			d = *argv;
> +		} else if (strcmp(*argv, "msti") == 0) {
> +			NEXT_ARG();
> +			m = *argv;
> +		} else if (strcmp(*argv, "state") == 0) {
> +			NEXT_ARG();
> +			s = *argv;
> +		} else {
> +			if (matches(*argv, "help") == 0)
> +				usage();
> +		}
> +		argc--; argv++;
> +	}
> +
> +	if (d == NULL || m == NULL || s == NULL) {
> +		fprintf(stderr, "Device, MSTI and state are required arguments.\n");
> +		return -1;
> +	}
> +
> +	req.ifi.ifi_index = ll_name_to_index(d);
> +	if (!req.ifi.ifi_index)
> +		return nodev(d);
> +
> +	msti = strtol(m, &endptr, 10);
> +	if (!(*s != '\0' && *endptr == '\0')) {
> +		fprintf(stderr,
> +			"Error: invalid MSTI\n");
> +		return -1;
> +	}
> +
> +	state = strtol(s, &endptr, 10);
> +	if (!(*s != '\0' && *endptr == '\0')) {
> +		state = parse_stp_state(s);
> +		if (state == -1) {
> +			fprintf(stderr,
> +				"Error: invalid STP port state\n");
> +			return -1;
>

Building with clang shows this problem.

    CC       mst.o
mst.c:215:13: warning: result of comparison of constant -1 with expression of type '__u8' (aka 'unsigned char') is always false [-Wtautological-constant-out-of-range-compare]
                if (state == -1) {
                    ~~~~~ ^  ~~
1 warning generated.