Re: [RFC PATCH v2 06/10] udp: cope with UDP GRO packet misdirection
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: 2018-10-22 20:01:32
On Fri, Oct 19, 2018 at 04:25:16PM +0200, Paolo Abeni wrote:
+
+static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
+ struct sk_buff *skb)
+{
+ struct sk_buff *segs;
+
+ /* the GSO CB lays after the UDP one, no need to save and restore any
+ * CB fragment, just initialize it
+ */
+ segs = __skb_gso_segment(skb, NETIF_F_SG, false);
+ if (unlikely(IS_ERR(segs)))
+ kfree_skb(skb);
+ else if (segs)
+ consume_skb(skb);
+ return segs;
+}
+
+One empty line too much.
quoted hunk ↗ jump to hunk
#define udp_portaddr_for_each_entry(__sk, list) \ hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 2331ac9de954..0d55145ce9f5 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c@@ -1909,7 +1909,7 @@ EXPORT_SYMBOL(udp_encap_enable); * Note that in the success and error cases, the skb is assumed to * have either been requeued or freed. */ -static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) +static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb) { struct udp_sock *up = udp_sk(sk); int is_udplite = IS_UDPLITE(sk);@@ -2012,6 +2012,29 @@ static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) return -1; } +void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto); + +static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) +{ + struct sk_buff *next, *segs; + int ret; + + if (likely(!udp_unexpected_gso(sk, skb))) + return udp_queue_rcv_one_skb(sk, skb); + + BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_SGO_CB_OFFSET); + __skb_push(skb, -skb_mac_offset(skb)); + segs = udp_rcv_segment(sk, skb); + for (skb = segs; skb; skb = next) { + next = skb->next; + __skb_pull(skb, skb_transport_offset(skb)); + ret = udp_queue_rcv_one_skb(sk, skb);
udp_queue_rcv_one_skb() starts with doing a xfrm4_policy_check(). Maybe we can do this on the GSO packet instead of the segments. So far this code is just for handling a corner case, but this might change.