This command resets the compression state and configures it according to the supplied "struct ngm_vjc_config" argument. This structure contains the following fields:
struct ngm_vjc_config {
u_char enableComp; /* Enable compression */
u_char enableDecomp; /* Enable decompression */
u_char maxChannel; /* Number of outgoing channels - 1 */
u_char compressCID; /* OK to compress outgoing CID’s */
};
When enableComp is set to zero, all packets received on the ip hook are forwarded unchanged out the vjip hook. Similarly, when enableDecomp is set to zero, all packets received on the vjip hook are forwarded unchanged out the ip hook, and packets are not accepted on the vjcomp and vjuncomp hooks. When a node is first created, both compression and decompression are disabled and the node is therefore operating in bi-directional "pass through" mode.
When enabling compression, maxChannel should be set to the number of outgoing compression channels minus one, and is a value between 3 and 15, inclusive. The compressCID field indicates whether it is OK to compress the CID header field for outgoing compressed TCP packets. This value should be zero unless either (a) it is not possible for an outgoing frame to be lost, or (b) lost frames can be reliably detected and immediately reported to the peer’s decompression engine (see NGM_VJC_RECV_ERROR below).
NGM_VJC_GET_STATE
This command returns the node’s current state described by the "struct slcompress" structure, which is defined in .In net/slcompress.h .
NGM_VJC_CLR_STATS
Clears the node statistics counters. Statistics are also cleared whenever the enableComp or enableDecomp fields are changed from zero to one by a NGM_VJC_SET_CONFIG control message.
NGM_VJC_RECV_ERROR
When the peer has CID header field compression enabled, this message must be sent to the local vjc node immediately after detecting that a received frame has been lost, due to a bad checksum or for any other reason. Failing to do this can result in corrupted TCP stream data.
