From 3868204d6b89ea373a273e760609cb08020beb1a Mon Sep 17 00:00:00 2001 From: "fan.du" Date: Sun, 1 Dec 2013 16:28:48 +0800 Subject: [PATCH] {pktgen, xfrm} Update IPv4 header total len and checksum after tranformation commit a553e4a6317b2cfc7659542c10fe43184ffe53da ("[PKTGEN]: IPSEC support") tried to support IPsec ESP transport transformation for pktgen, but acctually this doesn't work at all for two reasons(The orignal transformed packet has bad IPv4 checksum value, as well as wrong auth value, reported by wireshark) - After transpormation, IPv4 header total length needs update, because encrypted payload's length is NOT same as that of plain text. - After transformation, IPv4 checksum needs re-caculate because of payload has been changed. With this patch, armmed pktgen with below cofiguration, Wireshark is able to decrypted ESP packet generated by pktgen without any IPv4 checksum error or auth value error. pgset "flag IPSEC" pgset "flows 1" Signed-off-by: Fan Du Signed-off-by: David S. Miller --- net/core/pktgen.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 261357a..a797fff 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -2527,6 +2527,8 @@ static int process_ipsec(struct pktgen_dev *pkt_dev, if (x) { int ret; __u8 *eth; + struct iphdr *iph; + nhead = x->props.header_len - skb_headroom(skb); if (nhead > 0) { ret = pskb_expand_head(skb, nhead, 0, GFP_ATOMIC); @@ -2548,6 +2550,11 @@ static int process_ipsec(struct pktgen_dev *pkt_dev, eth = (__u8 *) skb_push(skb, ETH_HLEN); memcpy(eth, pkt_dev->hh, 12); *(u16 *) ð[12] = protocol; + + /* Update IPv4 header len as well as checksum value */ + iph = ip_hdr(skb); + iph->tot_len = htons(skb->len - ETH_HLEN); + ip_send_check(iph); } } return 1; -- 2.7.4