IPv4/v6: backports from upstream 2.6 kernel
kernel.org commits:
c137f3dda04b0aee1bc6889cdc69185f53df8a82 [TCP]: Fix NewReno's fast rexmit/recovery problems with GSOed skb
3eec0047d9bdd68fddef6539e77fee99ba2531f2 [TCP]: Fix mark_head_lost to ignore R-bit when trying to mark L
261ab365fadd53ddc1b292b1663800e11fbf3e71 [TCP]: Another TAGBITS -> SACKED_ACKED|LOST conversion
31ce8c71a3bdab12debb5899b1f6dac13e54c71d IPv6: Update Neighbor Cache when IPv6 RA is received on a router
14deae41566b5cdd992c01d0069518ced5227c83 IPv6: Fix sporadic sendmsg -EINVAL when sending to multicast groups