add IBC channel handshake

.gitignore

@@ -5,7 +5,7 @@ release/
 docs/tla/states/
 *.out
 vendor/
-build/
+/build/
 .vscode
 .idea
 __debug_*

docs/docs/build/modules/02-provider.md

@@ -29,6 +29,48 @@ The following diagram describes the phases of a consumer chain from the perspect
 
 ![Phases of a consumer chain](../../adrs/figures/adr19_phases_of_a_consumer_chain.png)
 
+## IBC Callbacks
+
+The consumer module is an IBC application that implements the [IBC module callback](https://ibc.cosmos.network/v8/ibc/apps/apps/#create-a-custom-ibc-application-module).
+
+### OnChanOpenInit
+
+`OnChanOpenInit` returns an error. `MsgChannelOpenInit` should be sent to the consumer. 
+
+### OnChanOpenTry
+
+`OnChanOpenTry` validates the parameters of the _CCV channel_ -- an ordered IBC channel connected on the `provider` port 
+and with the counterparty port set to `consumer` -- and asserts that the counterparty version matches the expected version 
+(only verions `1` is supported).
+
+If the validation passes, the provider module verifies that the underlying client is the expected client of the consumer chain 
+(i.e., the client created during the consumer chain launch) and that no other CCV channel exists for this consumer chain.
+
+Finally, it sets the [ProviderFeePoolAddr](./03-consumer.md#providerfeepooladdrstr) as part of the metadata.
+
+### OnChanOpenAck
+
+`OnChanOpenAck` returns an error. `MsgChannelOpenAck` should be sent to the consumer. 
+
+### OnChanOpenConfirm
+
+`OnChanOpenConfirm` first verifies that no other CCV channel exists for this consumer chain. Note that this is a sanity check.
+Then, it sets the channel mapping in the state.
+
+### OnChanCloseInit
+
+`OnChanCloseInit` returns an error. `MsgChannelCloseInit` should be sent to the consumer. 
+
+### OnChanCloseConfirm
+
+`OnChanCloseConfirm` is a no-op.
+
+### OnRecvPacket
+
+### OnAcknowledgementPacket
+
+### OnTimeoutPacket
+
 ## Messages
 
 ### MsgUpdateParams
@@ -401,8 +443,12 @@ message MsgSubmitConsumerDoubleVoting {
 
 ## Hooks
 
+> TBA
+
 ## Events
 
+> TBA
+
 ## Parameters
 
 The provider module contains the following parameters.
@@ -502,4 +548,10 @@ As a result, the provider chain can differentiate between
 _bonded validators_, i.e., validators that have stake locked on the provider chain, 
 and _active validator_, i.e., validators that participate actively in the provider chain's consensus. 
 
-## Client
+## Client
+
+### CLI
+
+### gRPC
+
+### REST

docs/docs/build/modules/03-consumer.md

@@ -25,6 +25,54 @@ As a result, the misbehaving validator is punished on the provider chain.
 
 ## State Transitions
 
+## IBC Callbacks
+
+The consumer module is an IBC application that implements the [IBC module callback](https://ibc.cosmos.network/v8/ibc/apps/apps/#create-a-custom-ibc-application-module).
+
+### OnChanOpenInit
+
+`OnChanOpenInit` first verifies that the CCV channel was not already created. 
+Then, it validates the channel parameters -- an ordered IBC channel connected on the `consumer` port 
+and with the counterparty port set to `provider` -- and asserts that the version matches the expected version 
+(only verions `1` is supported).
+
+Finally, it verifies that the underlying client is the expected client of the provider chain 
+(i.e., provided in the consumer module genesis state). 
+
+### OnChanOpenTry
+
+`OnChanOpenTry` returns an error. `MsgChannelOpenTry` should be sent to the provider. 
+
+### OnChanOpenAck
+
+`OnChanOpenAck` first verifies that the CCV channel was not already created. 
+Then it verifies that the counterparty version matches the expected version 
+(only verions `1` is supported).
+
+If the verification passes, it stores the [ProviderFeePoolAddr](#providerfeepooladdrstr) in the state.
+
+Finally, if the [DistributionTransmissionChannel](#distributiontransmissionchannel) parameter is not set,
+it initiate the opening handshake for a token transfer channel over the same connection as the CCV channel
+by calling the `ChannelOpenInit` method of the IBC module.
+
+### OnChanOpenConfirm
+
+`OnChanOpenConfirm` returns an error. `MsgChanOpenConfirm` should be sent to the provider. 
+
+### OnChanCloseInit
+
+`OnChanCloseInit` allow relayers to close duplicate OPEN channels, if the channel handshake is completed.
+
+### OnChanCloseConfirm
+
+`OnChanCloseConfirm` is a no-op.
+
+### OnRecvPacket
+
+### OnAcknowledgementPacket
+
+### OnTimeoutPacket
+
 ## Messages
 
 ### MsgUpdateParams
@@ -50,8 +98,12 @@ message MsgUpdateParams {
 
 ## Hooks
 
+> TBA
+
 ## Events
 
+> TBA
+
 ## Parameters
 
 :::warning
@@ -169,4 +221,10 @@ It is recommended that every consumer chain set and unbonding period shorter tha
 `RetryDelayPeriod` is the period at which the consumer retries to send a `SlashPacket` that was rejected by the provider.
 For more details, see [ADR-008](../adrs/adr-008-throttle-retries.md).
 
-## Client
+## Client
+
+### CLI
+
+### gRPC
+
+### REST