tuntap with tun_no_pi and X25 question
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From: andrew hendry on 24 Feb 2010 07:00 Setting up tun using X25, I can read X25 from the tun but cannot write to it, hitting this -EINVAL on write. /* Get packet from user space buffer */ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, const struct iovec *iv, size_t count, int noblock) { ..... case TUN_TUN_DEV: if (tun->flags & TUN_NO_PI) { switch (skb->data[0] & 0xf0) { case 0x40: pi.proto = htons(ETH_P_IP); break; case 0x60: pi.proto = htons(ETH_P_IPV6); break; default: tun->dev->stats.rx_dropped++; kfree_skb(skb); return -EINVAL; } } ..... The 0x40 and 0x60 comes from the first byte of the IP which has the version there? With X.25 the first byte changes depending on the call sequence, so it cant be detected and set in the same way. Is there a way to for a combination of TUNSETIFF with IFF_TUN | IFF_NO_PI and TUNSETLINK with ARPHRD_X25 to work? Probably all the non IP type protocols in if_arp.h have the same issue with IFF_NO_PI? thanks, Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Rémi Denis-Courmont on 24 Feb 2010 08:10
On Wed, 24 Feb 2010 22:52:27 +1100, andrew hendry <andrew.hendry(a)gmail.com> wrote: > The 0x40 and 0x60 comes from the first byte of the IP which has the > version there? Yes. > With X.25 the first byte changes depending on the call sequence, so it > cant be detected and set in the same way. Then you need to use PI. That's what it's meant for. -- Rémi Denis-Courmont http://www.remlab.net http://fi.linkedin.com/in/remidenis -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |