From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Shearman Subject: Re: [PATCH net-next v3 4/4] mpls: Allow payload type to be associated with label routes Date: Wed, 8 Apr 2015 15:03:29 +0100 Message-ID: <55253531.2020600@brocade.com> References: <1426866170-28739-1-git-send-email-rshearma@brocade.com> <1427739356-28113-1-git-send-email-rshearma@brocade.com> <1427739356-28113-5-git-send-email-rshearma@brocade.com> <87y4m3j1ol.fsf@x220.int.ebiederm.org> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Cc: "davem@davemloft.net" , "netdev@vger.kernel.org" To: "Eric W. Biederman" Return-path: Received: from mx0a-000f0801.pphosted.com ([67.231.144.122]:53024 "EHLO mx0a-000f0801.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751577AbbDHODf (ORCPT ); Wed, 8 Apr 2015 10:03:35 -0400 In-Reply-To: <87y4m3j1ol.fsf@x220.int.ebiederm.org> Sender: netdev-owner@vger.kernel.org List-ID: On 07/04/15 18:19, Eric W. Biederman wrote: > Robert Shearman writes: > >> RFC 4182 s2 states that if an IPv4 Explicit NULL label is the only >> label on the stack, then after popping the resulting packet must be >> treated as a IPv4 packet and forwarded based on the IPv4 header. The >> same is true for IPv6 Explicit NULL with an IPv6 packet following. >> >> Therefore, when installing the IPv4/IPv6 Explicit NULL label routes, >> add an attribute that specifies the expected payload type for use at >> forwarding time for determining the type of the encapsulated packet >> instead of inspecting the first nibble of the packet. > > This looks pretty reasonable. > > I suspect the multiple returns instead of using a single variable > might generate slightly worse machine but whatever. That's a good point - the way the changes are structured now means that the removal of the local variable doesn't add anything, so if it's OK with you I'll change that. > > Acked-by: "Eric W. Biederman" Thanks for the review Eric. Rob > > >> Cc: "Eric W. Biederman" >> Signed-off-by: Robert Shearman >> --- >> net/mpls/af_mpls.c | 72 ++++++++++++++++++++++++++++++++---------------------- >> 1 file changed, 43 insertions(+), 29 deletions(-) >> >> diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c >> index 0b0420bf110d..e9ce5799449d 100644 >> --- a/net/mpls/af_mpls.c >> +++ b/net/mpls/af_mpls.c >> @@ -23,13 +23,25 @@ >> /* This maximum ha length copied from the definition of struct neighbour */ >> #define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))) >> >> +enum mpls_payload_type { >> + MPT_UNSPEC, /* IPv4 or IPv6 */ >> + MPT_IPV4 = 4, >> + MPT_IPV6 = 6, >> + >> + /* Other types not implemented: >> + * - Pseudo-wire with or without control word (RFC4385) >> + * - GAL (RFC5586) >> + */ >> +}; >> + >> struct mpls_route { /* next hop label forwarding entry */ >> struct net_device __rcu *rt_dev; >> struct rcu_head rt_rcu; >> u32 rt_label[MAX_NEW_LABELS]; >> u8 rt_protocol; /* routing protocol that set this entry */ >> u8 rt_unlabeled : 1; >> - u8 rt_labels : 7; >> + u8 rt_payload_type : 3; >> + u8 rt_labels : 4; >> u8 rt_via_alen; >> u8 rt_via_table; >> u8 rt_via[0]; >> @@ -90,16 +102,7 @@ static bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) >> static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb, >> struct mpls_entry_decoded dec) >> { >> - /* RFC4385 and RFC5586 encode other packets in mpls such that >> - * they don't conflict with the ip version number, making >> - * decoding by examining the ip version correct in everything >> - * except for the strangest cases. >> - * >> - * The strange cases if we choose to support them will require >> - * manual configuration. >> - */ >> - struct iphdr *hdr4; >> - bool success = true; >> + enum mpls_payload_type payload_type; >> >> /* The IPv4 code below accesses through the IPv4 header >> * checksum, which is 12 bytes into the packet. >> @@ -114,24 +117,31 @@ static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb, >> if (!pskb_may_pull(skb, 12)) >> return false; >> >> - /* Use ip_hdr to find the ip protocol version */ >> - hdr4 = ip_hdr(skb); >> - if (hdr4->version == 4) { >> + payload_type = rt->rt_payload_type; >> + if (payload_type == MPT_UNSPEC) >> + payload_type = ip_hdr(skb)->version; >> + >> + switch (payload_type) { >> + case MPT_IPV4: { >> + struct iphdr *hdr4 = ip_hdr(skb); >> skb->protocol = htons(ETH_P_IP); >> csum_replace2(&hdr4->check, >> htons(hdr4->ttl << 8), >> htons(dec.ttl << 8)); >> hdr4->ttl = dec.ttl; >> + return true; >> } >> - else if (hdr4->version == 6) { >> + case MPT_IPV6: { >> struct ipv6hdr *hdr6 = ipv6_hdr(skb); >> skb->protocol = htons(ETH_P_IPV6); >> hdr6->hop_limit = dec.ttl; >> + return true; >> + } >> + case MPT_UNSPEC: >> + break; >> } >> - else >> - /* version 0 and version 1 are used by pseudo wires */ >> - success = false; >> - return success; >> + >> + return false; >> } >> >> static int mpls_forward(struct sk_buff *skb, struct net_device *dev, >> @@ -254,16 +264,17 @@ static const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = { >> }; >> >> struct mpls_route_config { >> - u32 rc_protocol; >> - u32 rc_ifindex; >> - u16 rc_via_table; >> - u16 rc_via_alen; >> - u8 rc_via[MAX_VIA_ALEN]; >> - u32 rc_label; >> - u32 rc_output_labels; >> - u32 rc_output_label[MAX_NEW_LABELS]; >> - u32 rc_nlflags; >> - struct nl_info rc_nlinfo; >> + u32 rc_protocol; >> + u32 rc_ifindex; >> + u16 rc_via_table; >> + u16 rc_via_alen; >> + u8 rc_via[MAX_VIA_ALEN]; >> + u32 rc_label; >> + u32 rc_output_labels; >> + u32 rc_output_label[MAX_NEW_LABELS]; >> + u32 rc_nlflags; >> + enum mpls_payload_type rc_payload_type; >> + struct nl_info rc_nlinfo; >> }; >> >> static struct mpls_route *mpls_rt_alloc(size_t alen) >> @@ -414,6 +425,7 @@ static int mpls_route_add(struct mpls_route_config *cfg) >> } >> rt->rt_protocol = cfg->rc_protocol; >> RCU_INIT_POINTER(rt->rt_dev, dev); >> + rt->rt_payload_type = cfg->rc_payload_type; >> rt->rt_via_table = cfg->rc_via_table; >> memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen); >> >> @@ -949,6 +961,7 @@ static int resize_platform_label_table(struct net *net, size_t limit) >> goto nort0; >> RCU_INIT_POINTER(rt0->rt_dev, lo); >> rt0->rt_protocol = RTPROT_KERNEL; >> + rt0->rt_payload_type = MPT_IPV4; >> rt0->rt_via_table = NEIGH_LINK_TABLE; >> memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len); >> } >> @@ -959,6 +972,7 @@ static int resize_platform_label_table(struct net *net, size_t limit) >> goto nort2; >> RCU_INIT_POINTER(rt2->rt_dev, lo); >> rt2->rt_protocol = RTPROT_KERNEL; >> + rt2->rt_payload_type = MPT_IPV6; >> rt2->rt_via_table = NEIGH_LINK_TABLE; >> memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len); >> }