Re: [PATCH] net: IP_NODEFRAG option for IPv4 socket

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mardi 15 juin 2010 à 08:53 +0200, Jiri Olsa a écrit :
> hi,
> 
> I prepared the patch implementing IP_NODEFRAG option for IPv4 socket.
> The reason is, there's no other way to send out the packet with user
> customized header of the reassembly part.
> 

Obviously, you need to update documentation and man pages as well.

MAN-PAGES: MANUAL PAGES FOR LINUX -- Sections 2, 3, 4, 5, and 7
M:	Michael Kerrisk <mtk.manpages@gmail.com>
W:	http://www.kernel.org/doc/man-pages
L:	linux-man@vger.kernel.org
S:	Maintained


> wbr,
> jirka
> 
> 
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> ---
> diff --git a/include/linux/in.h b/include/linux/in.h
> index 583c76f..41d88a4 100644
> --- a/include/linux/in.h
> +++ b/include/linux/in.h
> @@ -85,6 +85,7 @@ struct in_addr {
>  #define IP_RECVORIGDSTADDR   IP_ORIGDSTADDR
>  
>  #define IP_MINTTL       21
> +#define IP_NODEFRAG     22
>  
>  /* IP_MTU_DISCOVER values */
>  #define IP_PMTUDISC_DONT		0	/* Never send DF frames */
> diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
> index 1653de5..1989cfd 100644
> --- a/include/net/inet_sock.h
> +++ b/include/net/inet_sock.h
> @@ -137,7 +137,8 @@ struct inet_sock {
>  				hdrincl:1,
>  				mc_loop:1,
>  				transparent:1,
> -				mc_all:1;
> +				mc_all:1,
> +				nodefrag:1;
>  	int			mc_index;
>  	__be32			mc_addr;
>  	struct ip_mc_socklist	*mc_list;
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index 551ce56..84d2c8e 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -355,6 +355,8 @@ lookup_protocol:
>  	inet = inet_sk(sk);
>  	inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
>  
> +	inet->nodefrag = 0;
> +

Hmm... what about cloning ?

>  	if (SOCK_RAW == sock->type) {
>  		inet->inet_num = protocol;
>  		if (IPPROTO_RAW == protocol)
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index ce23178..d8196e1 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -449,7 +449,7 @@ static int do_ip_setsockopt(struct sock *sk, int level,
>  			     (1<<IP_MTU_DISCOVER) | (1<<IP_RECVERR) |
>  			     (1<<IP_ROUTER_ALERT) | (1<<IP_FREEBIND) |
>  			     (1<<IP_PASSSEC) | (1<<IP_TRANSPARENT) |
> -			     (1<<IP_MINTTL))) ||
> +			     (1<<IP_MINTTL) | (1<<IP_NODEFRAG))) ||
>  	    optname == IP_MULTICAST_TTL ||
>  	    optname == IP_MULTICAST_ALL ||
>  	    optname == IP_MULTICAST_LOOP ||
> @@ -572,6 +572,13 @@ static int do_ip_setsockopt(struct sock *sk, int level,
>  		}
>  		inet->hdrincl = val ? 1 : 0;
>  		break;
> +	case IP_NODEFRAG:
> +		if (sk->sk_type != SOCK_RAW) {
> +			err = -ENOPROTOOPT;
> +			break;
> +		}
> +		inet->nodefrag = val ? 1 : 0;
> +		break;
>  	case IP_MTU_DISCOVER:
>  		if (val < IP_PMTUDISC_DONT || val > IP_PMTUDISC_PROBE)
>  			goto e_inval;
> diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c b/net/ipv4/netfilter/nf_defrag_ipv4.c
> index cb763ae..eab8de3 100644
> --- a/net/ipv4/netfilter/nf_defrag_ipv4.c
> +++ b/net/ipv4/netfilter/nf_defrag_ipv4.c
> @@ -66,6 +66,11 @@ static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
>  					  const struct net_device *out,
>  					  int (*okfn)(struct sk_buff *))
>  {
> +	struct inet_sock *inet = inet_sk(skb->sk);
> +
> +	if (inet && inet->nodefrag)
> +		return NF_ACCEPT;
> +
>  #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
>  #if !defined(CONFIG_NF_NAT) && !defined(CONFIG_NF_NAT_MODULE)
>  	/* Previously seen (loopback)?  Ignore.  Do this before
> --
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