From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id BA46740C63 for ; Mon, 7 Feb 2022 00:01:53 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id D21DB68B1D2; Mon, 7 Feb 2022 02:01:50 +0200 (EET) Received: from mail-pl1-f170.google.com (mail-pl1-f170.google.com [209.85.214.170]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id B18D268B132 for ; Mon, 7 Feb 2022 02:01:44 +0200 (EET) Received: by mail-pl1-f170.google.com with SMTP id z5so9875200plg.8 for ; Sun, 06 Feb 2022 16:01:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=Tu+LEVab0IHgl/jQL9tVnX/TqGZQXYQuhGl/BFcSMS4=; b=c/7/MdZdUipxFRgRf4ivxrymorfJN5wEhiULQESzH7X7w+dAyPD09wgoaOPiB31LfN GHQkpkHxeUZd8XRxZoXyMoTwWhnd1dwbFx3og0b2jHazpEAl8o4b9oog9V0HXZ8YaVDB waQSpB0muY2UmMqZ5GPzzqLFz+ld4jv4aq0N0mltbXoz8fxxn9X7hdq1zUMTARWp2oe+ hZG0n/W+ColANg2tN8AWe0jMzYUg6Cuq61tOsB1tY+2tUiVbucrzjbPZ61sqDQqFdQ2t Tky8rK8/2trTL180EfXR4XWw/Vvz4IFrgAcE6CXVtwy/+MdJUMyCoyKDX6XoY3N/M0Lw ntvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:subject:message-id:mail-followup-to :references:mime-version:content-disposition:in-reply-to; bh=Tu+LEVab0IHgl/jQL9tVnX/TqGZQXYQuhGl/BFcSMS4=; b=t4yQ6IEP9gyl/cmKq4hRFj7gK17kuDueOs5H21LaH81AX3KOHlHiQTyPjmtvlyFYGZ anQqbSrG+GHDQv9c/07uvRImiJNXuhB9b6UOCkklkzSs+YUm0JsFphd/rzU2erRzpz1k hfnj6rbskFKbmIB1FA8nmDbmhiBpFPP1z/ZE2iWT8RJDwuiHKmNQuX6Q3nWuYcOrtCA8 eHVpnrqq+61sETlGrM3NFxC2CfSp0dCJWRZtW+x5A/mH/oM3B8k8gQbLdGmFl4NRt6Yb sLqfkQSKHoUyU5EyHw4JE8lImeGY9ym7b6IXMhwrrSI7pGPz5yu1O/tT0EPY0G0670By OH7g== X-Gm-Message-State: AOAM5319b/YJzXELvfSqRIYo4qgfxDtbI/y6d5Pj5puFTtnymFN0YNpo A+ph9iG5e60cUVL/yA0jPi56wwYzjuc= X-Google-Smtp-Source: ABdhPJwNJvy9evltje2MmLrgQ0rug8tdmMq6/bdUZveBotjrDXC7PYKAcQZXbiUqMezm5onRZWr3QA== X-Received: by 2002:a17:902:bc83:: with SMTP id bb3mr14168704plb.172.1644192102059; Sun, 06 Feb 2022 16:01:42 -0800 (PST) Received: from gmail.com ([161.117.202.209]) by smtp.gmail.com with ESMTPSA id j15sm10113752pfj.102.2022.02.06.16.01.40 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 06 Feb 2022 16:01:41 -0800 (PST) Date: Mon, 7 Feb 2022 08:01:38 +0800 From: lance.lmwang@gmail.com To: ffmpeg-devel@ffmpeg.org Message-ID: <20220207000138.GA12778@gmail.com> Mail-Followup-To: ffmpeg-devel@ffmpeg.org References: <1643260580-25792-1-git-send-email-lance.lmwang@gmail.com> <1644038899-15433-1-git-send-email-lance.lmwang@gmail.com> <1644038899-15433-2-git-send-email-lance.lmwang@gmail.com> <20220206020933.GA29837@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Subject: Re: [FFmpeg-devel] [PATCH v2 2/3] avformat/udp: Fix IP_MULTICAST_TTL for BSD compatibility X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On Sun, Feb 06, 2022 at 02:27:09PM -0800, Chad Fraleigh wrote: > > On 2/5/2022 6:09 PM, lance.lmwang@gmail.com wrote: > > On Sat, Feb 05, 2022 at 01:26:18PM -0800, Chad Fraleigh wrote: > >> Since any [valid] value over 255 is impossible in the IPv4 protocol (the TTL field is only 8-bits), it should always be capped at 255 (for consistency) or return an invalid value error (the one I would suggest). > >> > > > > zhilizhao have submit a patch to limit the range of ttl from option. Do you want > > to return an invalid error here still? > > If it can never be called with an invalid value, not even programmatically if someone links against the ffmpeg libs, then checking it is unneeded. But also checking it to limit the unsigned char value would be redundant, so only the value cast would be needed, i.e.: > > ttl = (unsigned char) mcastTTL; Yes, checking is unneeded anymore, I'll remove it locally. > > > If however, it could be called without being first limited, then returning an error would be best to avoid silently having unexpected results. Also, checking that it isn't negative should be done in that case. Not counting pending patches, I only see udp_open() calls it, so if it's already bound in there, no extra checks are needed. Sure, the patch will be applied after the pending patches for limit anyway if nobody have other comments. > > Of course, these are only suggestions, since I'm a nobody. =) > > > >> Despite VLC's reversed comment, using an int seems to be the exception to the rule (i.e. only linux and windows seem to use it [as-documented]), perhaps doing the unsigned char first and using the int as the fallback would be better? It's not really just a BSD thing, unless you also count LWIP and Solaris as BSD. Unless VLC's code history shows them doing it this way at one time and swapping it (but forgetting the comment) to fix a known bug? > >> > > > > I have blamed vlc code and sure the code doing it this way at one time(104938796a3). > > For the mismatch of code and comments, I prefer to code always as code were build > > and used by all kinds of system which vlc is supported already. > > > > As for use BSD, I prefer to count LWIP and Solaris into BSD category which using > > rule of byte. If you still prefer to add them into comments, I'm OK also. > > > >> > >> On 2/4/2022 9:28 PM, lance.lmwang@gmail.com wrote: > >>> From: Limin Wang > >>> > >>> Suggested by zhilizhao, vlc project has solved the compatibility by > >>> the same way, so I borrowed the comments from vlc project. > >>> > >>> Fix #ticket9449 > >>> > >>> Signed-off-by: Limin Wang > >>> --- > >>> libavformat/udp.c | 15 +++++++++++++-- > >>> 1 file changed, 13 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/libavformat/udp.c b/libavformat/udp.c > >>> index 3dc79eb..34488d6 100644 > >>> --- a/libavformat/udp.c > >>> +++ b/libavformat/udp.c > >>> @@ -164,6 +164,10 @@ static int udp_set_multicast_ttl(int sockfd, int mcastTTL, > >>> { > >>> int protocol, cmd; > >>> > >>> + /* There is some confusion in the world whether IP_MULTICAST_TTL > >>> + * takes a byte or an int as an argument. > >>> + * BSD seems to indicate byte so we are going with that and use > >>> + * int as a fallback to be safe */ > >>> switch (addr->sa_family) { > >>> #ifdef IP_MULTICAST_TTL > >>> case AF_INET: > >>> @@ -183,8 +187,15 @@ static int udp_set_multicast_ttl(int sockfd, int mcastTTL, > >>> } > >>> > >>> if (setsockopt(sockfd, protocol, cmd, &mcastTTL, sizeof(mcastTTL)) < 0) { > >>> - ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt"); > >>> - return ff_neterrno(); > >>> + /* BSD compatibility */ > >>> + unsigned char ttl; > >>> + > >>> + ff_log_net_error(logctx, AV_LOG_DEBUG, "setsockopt"); > >>> + ttl = (unsigned char)(( mcastTTL > 255 ) ? 255 : mcastTTL); > >>> + if (setsockopt(sockfd, protocol, cmd, &ttl, sizeof(ttl)) < 0) { > >>> + ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt"); > >>> + return ff_neterrno(); > >>> + } > >>> } > >>> > >>> return 0; > >> _______________________________________________ > >> ffmpeg-devel mailing list > >> ffmpeg-devel@ffmpeg.org > >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > >> > >> To unsubscribe, visit link above, or email > >> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". -- Thanks, Limin Wang _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".