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authorGary S. Robertson <gary.robertson@linaro.org>2014-01-22 11:06:54 -0600
committerGary S. Robertson <gary.robertson@linaro.org>2014-01-22 11:06:54 -0600
commita7fd051cd1119af788dd161a4c834b06377d76a8 (patch)
tree80368fccae171d1b0446f3e2b4fd4d9b43e65cbe /Documentation/networking/packet_mmap.txt
parent00629ac158e1be3124b796078cf0347b946cb053 (diff)
parent1071ea6e68ead40df739b223e9013d99c23c19ab (diff)
Merge tag 'v3.10.27' of git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable into linux-lnglinux-lng-3.10.27-2014.02
This is the 3.10.27 stable release
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diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index 23dd80e82b8e..0f4376ec8852 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt
@@ -123,6 +123,16 @@ Transmission process is similar to capture as shown below.
[shutdown] close() --------> destruction of the transmission socket and
deallocation of all associated resources.
+Socket creation and destruction is also straight forward, and is done
+the same way as in capturing described in the previous paragraph:
+
+ int fd = socket(PF_PACKET, mode, 0);
+
+The protocol can optionally be 0 in case we only want to transmit
+via this socket, which avoids an expensive call to packet_rcv().
+In this case, you also need to bind(2) the TX_RING with sll_protocol = 0
+set. Otherwise, htons(ETH_P_ALL) or any other protocol, for example.
+
Binding the socket to your network interface is mandatory (with zero copy) to
know the header size of frames used in the circular buffer.