From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D6D4441DECF for ; Wed, 15 Jul 2026 15:03:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784127781; cv=none; b=DEThuBtDT5JZeLAHl/qOZaWnR0vS3vlvDcRlznvmP+RtMKID59glvDaHtXjCzRZOuLMOFOKeM/EJh/KkZcCvnWGhGBhMegyJ87twYE8LEJNz8E2NvnrWE5+CCQF8SfJbPVHCgQqDvNcywq9juxWE0sxQft17G+ToUgqcZM1s3BM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784127781; c=relaxed/simple; bh=BT4NCCefGBEHg9Oqy1ef01/bhz/T6gxhIP1pP8s+y1w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IROsDyewSUzqLQ/v7zI7sV3EKciKflzQPL9R/TebuFmxhjNuu5ZjYvZ9sIdSPuCdie84JvAGDo9BkauztbgRVY1mDIZXPBL5VtwX2z6R2iiHdLXo06zpvrMIlEUlp4TESummMlzvgXsbz0ub+qZMQ7a/dDHNkaOMUtM9ZFxcNeo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RJzhNnpG; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RJzhNnpG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 636531F00A3A; Wed, 15 Jul 2026 15:03:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784127780; bh=wDNmqqm3V2brDMwyu7i/iBciQvN4pYkMed4wykoEK6k=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=RJzhNnpGnWYQ5RcTbk1utzRvoSZDYMpXu59ptMyCf5R/AGY4tAIJ5AYDXi1CkTDoC y6ZrUIMNKaSBEU7Cv1L/jfK2gaPG/Dxxe18CAChv2eTJbpwf+Tdtyfwcpvm/pTnJku Ci29pLVmweh26/+iHtPymFpWYKW8/WVlXgWePq0zHpPl2cH8Eee8nWVRoX1izras0u D590sSfgfjgHMAZTBBrwPj+aW0ln8PQtDzXT3ts4sad+7PhEuknaLdOCD13vAJ5yM6 hzpn6W9B+BlPLgzB4CHQTHI7ZWa0YSgcBI5ZI8GuRD7tGW8iWnacJ8ZmjgYxnkmouP CH7wmMdlxVjcA== Message-ID: <01009484-2a68-4b44-b742-bee13bbb08b2@kernel.org> Date: Wed, 15 Jul 2026 09:02:59 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH iproute2-next] ipmaddr: use RTM_GETMULTICAST to list multicast addresses Content-Language: en-US To: Yuyang Huang Cc: netdev@vger.kernel.org References: <20260711030733.48567-1-sigefriedhyy@gmail.com> From: David Ahern In-Reply-To: <20260711030733.48567-1-sigefriedhyy@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 7/10/26 9:07 PM, Yuyang Huang wrote: > +static int accept_maddr(struct nlmsghdr *n, void *arg) > +{ > + struct maddr_dump_ctx *ctx = arg; > + struct ifaddrmsg *ifm = NLMSG_DATA(n); > + int len = n->nlmsg_len - NLMSG_LENGTH(sizeof(*ifm)); > + struct rtattr *tb[IFA_MAX + 1]; > + struct ma_info *ma; > + > + if (n->nlmsg_type != RTM_GETMULTICAST && > + n->nlmsg_type != RTM_NEWMULTICAST) > + return 0; >From claude (and I agree with the finding) > +static int accept_maddr(struct nlmsghdr *n, void *arg) > +{ > ... > + if (n->nlmsg_type != RTM_GETMULTICAST && > + n->nlmsg_type != RTM_NEWMULTICAST) > + return 0; The kernel replies to a RTM_GETMULTICAST dump request with RTM_NEWMULTICAST messages — it never sends RTM_GETMULTICAST in a response. Including RTM_GETMULTICAST in the guard is dead code and is confusing; it inverts the usual convention used everywhere else in iproute2 (e.g. ipaddress.c always checks RTM_NEW* / RTM_DEL*, never RTM_GET*). Should be: if (n->nlmsg_type != RTM_NEWMULTICAST) return 0;