[PATCH V2 2/2] af_packet: pass checksum validation status to the user
From: Alexander Drozdov <hidden>
Date: 2015-03-23 06:11:45
Also in:
linux-api, lkml
Subsystem:
documentation, networking drivers, networking [general], packet sockets, the rest · Maintainers:
Jonathan Corbet, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Willem de Bruijn, Linus Torvalds
Introduce TP_STATUS_CSUM_VALID tp_status flag to tell the af_packet user that at least the transport header checksum has been already validated. For now, the flag may be set for incoming packets only. Signed-off-by: Alexander Drozdov <redacted> Cc: Willem de Bruijn <willemb@google.com> --- Documentation/networking/packet_mmap.txt | 13 ++++++++++--- include/uapi/linux/if_packet.h | 1 + net/packet/af_packet.c | 9 +++++++++ 3 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index a6d7cb9..daa015a 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt@@ -440,9 +440,10 @@ and the following flags apply: +++ Capture process: from include/linux/if_packet.h - #define TP_STATUS_COPY 2 - #define TP_STATUS_LOSING 4 - #define TP_STATUS_CSUMNOTREADY 8 + #define TP_STATUS_COPY (1 << 1) + #define TP_STATUS_LOSING (1 << 2) + #define TP_STATUS_CSUMNOTREADY (1 << 3) + #define TP_STATUS_CSUM_VALID (1 << 7) TP_STATUS_COPY : This flag indicates that the frame (and associated meta information) has been truncated because it's
@@ -466,6 +467,12 @@ TP_STATUS_CSUMNOTREADY: currently it's used for outgoing IP packets which reading the packet we should not try to check the checksum. +TP_STATUS_CSUM_VALID : This flag indicates that at least the transport + header checksum of the packet has been already + validated on the kernel side. If the flag is not set + then we are free to check the checksum by ourselves + provided that TP_STATUS_CSUMNOTREADY is also not set. + for convenience there are also the following defines: #define TP_STATUS_KERNEL 0
diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h
index da2d668..053bd10 100644
--- a/include/uapi/linux/if_packet.h
+++ b/include/uapi/linux/if_packet.h@@ -99,6 +99,7 @@ struct tpacket_auxdata { #define TP_STATUS_VLAN_VALID (1 << 4) /* auxdata has valid tp_vlan_tci */ #define TP_STATUS_BLK_TMO (1 << 5) #define TP_STATUS_VLAN_TPID_VALID (1 << 6) /* auxdata has valid tp_vlan_tpid */ +#define TP_STATUS_CSUM_VALID (1 << 7) /* Tx ring - header status */ #define TP_STATUS_AVAILABLE 0
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 6ecf8dd..3f09dda 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c@@ -1918,6 +1918,10 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, if (skb->ip_summed == CHECKSUM_PARTIAL) status |= TP_STATUS_CSUMNOTREADY; + else if (skb->pkt_type != PACKET_OUTGOING && + (skb->ip_summed == CHECKSUM_COMPLETE || + skb_csum_unnecessary(skb))) + status |= TP_STATUS_CSUM_VALID; if (snaplen > res) snaplen = res;
@@ -3015,6 +3019,11 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, aux.tp_status = TP_STATUS_USER; if (skb->ip_summed == CHECKSUM_PARTIAL) aux.tp_status |= TP_STATUS_CSUMNOTREADY; + else if (skb->pkt_type != PACKET_OUTGOING && + (skb->ip_summed == CHECKSUM_COMPLETE || + skb_csum_unnecessary(skb))) + aux.tp_status |= TP_STATUS_CSUM_VALID; + aux.tp_len = PACKET_SKB_CB(skb)->origlen; aux.tp_snaplen = skb->len; aux.tp_mac = 0;
--
1.9.1