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[DASH] Undeprecate ENI table pl_sip_encoding (sonic-net#1805)
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[DASH] Undeprecate ENI table pl_sip_encoding (sonic-net#1805)
* pl_sip_encoding was recently undeprecated, so update the HLD accordingly.
* Update privatelink configuration examples to reflect pl_sip_encoding
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@theasianpianist @a114j0y
theasianpianist authored and a114j0y committed Oct 23, 2024
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Showing 1 changed file with 84 additions and 53 deletions.
137 changes: 84 additions & 53 deletions doc/dash/dash-sonic-hld.md
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Original file line number Diff line number Diff line change
Expand Up @@ -362,7 +362,7 @@ DASH_ENI_TABLE:{{eni}}
"underlay_ip": {{ip_addr}}
"admin_state": {{enabled/disabled}}
"vnet": {{vnet_name}}
"pl_sip_encoding": {{ip_prefix}} (OPTIONAL) (OBSOLETED)
"pl_sip_encoding": {{ip_prefix}} (OPTIONAL)
"pl_underlay_sip": {{ip_addr}} (OPTIONAL)
"v4_meter_policy_id": {{string}} (OPTIONAL)
"v6_meter_policy_id": {{string}} (OPTIONAL)
Expand All @@ -376,8 +376,7 @@ qos = Associated Qos profile
underlay_ip = PA address for Inbound encapsulation to VM
admin_state = Enabled after all configurations are applied.
vnet = Vnet that ENI belongs to
pl_sip_encoding = Private Link encoding for IPv6 SIP transpositions; Format "field_value/full_mask" where both field_value and `full_mask` must be given as IPv6 addresses. field_value must be used as a replacement to the
first (128-len(full_mask)) bits of pl_sip. Last 32 bits are reserved for the IPv4 CA. Logic: ((pl_sip & !full_mask) | field_value). (Obsoleted - Will use overlay transpositions from mapping tables)
pl_sip_encoding = Privatelink encoding for IPv6 SIP transformation; Format `field_value/full_mask` where both `field_value` and `full_mask` must be given as IPv6 addresses. See "3.6.3.2 PL IPv6 Address Transformation" for details.
pl_underlay_sip = Underlay SIP (ST GW VIP) to be used for all private link transformation for this ENI
v4_meter_policy_id = IPv4 meter policy ID
v6_meter_policy_id = IPv6 meter policy ID
Expand Down Expand Up @@ -611,8 +610,8 @@ underlay_ip = ip_address ; PA address for the CA
mac_address = MAC address as string ; Inner dst mac
metering_class_or = uint32 ; metering class 'or' bits
use_dst_vni = bool ; if true, use the destination VNET VNI for encap. If false or not specified, use source VNET's VNI
overlay_sip_prefix = ip_prefix ; overlay src ip prefix if routing_type is {privatelink}, transform last 32 bits from packet if mask is 96
overlay_dip_prefix = ip_prefix ; overlay dst ip prefix if routing_type is {privatelink}
overlay_sip_prefix = ip_prefix ; overlay src ip prefix if routing_type is {privatelink}. Format `field_value/full_mask` where both `field_value` and `full_mask` must be IPv6 addresses. See "3.6.3.2 PL IPv6 Address Transformation" for details.
overlay_dip_prefix = ip_prefix ; overlay dst ip prefix if routing_type is {privatelink}. Format `field_value/full_mask` where both `field_value` and `full_mask` must be IPv6 addresses. See "3.6.3.2 PL IPv6 Address Transformation" for details.
routing_appliance_id = uint32 ; ID of routing appliance to use if routing_type is {privatelinknsg} (OBSOLETED)
tunnel = string ; Nexthop tunnel for privatelink nsg for additional encapsulation.
```
Expand Down Expand Up @@ -1407,6 +1406,7 @@ For the example configuration above, the following is a brief explanation of loo

### 3.6.3 Private Link

#### 3.6.3.1 PL Sample Configuration
```
[
{
Expand Down Expand Up @@ -1439,7 +1439,8 @@ For the example configuration above, the following is a brief explanation of loo
"underlay_ip": "25.1.1.1",
"admin_state": "enabled",
"vnet": "Vnet1",
"pl_underlay_sip": "55.1.2.3"
"pl_underlay_sip": "55.1.2.3",
"pl_sip_encoding": "::cb3a:16e5:ff71:0:0/::ffff:ffff:ffff:0:0"
},
"OP": "SET"
},
Expand Down Expand Up @@ -1470,8 +1471,8 @@ For the example configuration above, the following is a brief explanation of loo
"routing_type":"privatelink",
"mac_address":"F9-22-83-99-22-A2",
"underlay_ip":"50.1.2.3",
"overlay_sip_prefix":"fd41:108:20:d204::0/96",
"overlay_dip_prefix":"2603:10e1:100:2::3401:203/128",
"overlay_sip_prefix":"fd41:108:20:abc:abc::0/ffff:ffff:ffff:ffff:ffff:ffff::",
"overlay_dip_prefix":"2603:10e1:100:2::3401:203/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
"metering_class_or":"0x06",
},
"OP": "SET"
Expand All @@ -1488,8 +1489,8 @@ For the example configuration above, the following is a brief explanation of loo
"routing_type":"privatelink",
"mac_address":"F9-22-83-99-22-A2",
"underlay_ip":"50.2.2.6",
"overlay_sip_prefix":"fd41:108:20:d204::200::0/96",
"overlay_dip_prefix":"2603:10e1:100:2::3402:206/128",
"overlay_sip_prefix":"ccc4:ac57:2546::/ffff:ffff:ffff::",
"overlay_dip_prefix":"3332:0f1c:2878:c130:d6a0:a997:aa33:c63d/ffff:ffff:ffff:ffff:ffff:ffff::",
},
"OP": "SET"
},
Expand All @@ -1498,8 +1499,8 @@ For the example configuration above, the following is a brief explanation of loo
"routing_type":"privatelink",
"mac_address":"F9-22-83-99-22-A2",
"underlay_ip":"50.2.2.6",
"overlay_sip_prefix":"fd41:108:20:d204::200::0/96",
"overlay_dip_prefix":"2603:10e1:100:2::3402:206/128",
"overlay_sip_prefix":"35ea:8ec2:e511::/ffff:ffff:ffff::",
"overlay_dip_prefix":"f409:6491:d18e:d3ff:ad7a:3b6e:0702:a92a/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
"tunnel":"nsg_tunnel_1"
},
"OP": "SET"
Expand Down Expand Up @@ -1529,44 +1530,74 @@ For the example configuration above, the following is a brief explanation of loo

For the example configuration above, the following is a brief explanation of lookup behavior in the outbound direction:

1. Packet destined to 10.1.0.8 from 10.1.1.1:
a. LPM lookup hits for entry 10.1.0.8/32
b. The action in this case is "vnet"
c. Next lookup is in the mapping table and mapping table action here is "privatelink"
d. First Action for "privatelink" is 4to6 transposition
e. Packet gets transformed as:
For Overlay SIP, use Overlay SIP prefix -> Overlay SIP fd41:108:20:d204::a01:101 using the following logic:
result = overlay_sip_prefix | 10.1.1.1 (insert source CA to last 32 bits)
Overlay DIP 2603:10e1:100:2::3401:203 (No transformation, provided as part of mapping)
f. Second Action is Static NVGRE encap with GRE key '100'.
g. Underlay DIP shall be 50.1.2.3 (from mapping), Underlay SIP shall be 55.1.2.3 (from ENI)
h. Metering:
- LPM route has metering bits configured
- Aggregated OR - 0x66
- Aggregated AND - 0x77
- Metering class is derived from (Agreggated OR & Agreggated AND) -> 0x66 used for accounting the traffic

2. Packet destined to 10.2.0.6 from 10.1.1.2:
a. LPM lookup hits for entry 10.2.0.0/24
b. The action in this case is "vnet"
c. Next lookup is in the mapping table and mapping table action here is "privatelink"
d. First Action for "privatelink" is 4to6 transposition
e. Packet gets transformed as:
For Overlay SIP, use Overlay SIP prefix -> Overlay SIP fd41:108:20:d204::200:a02:6;
Overlay DIP 2603:10e1:100:2::3402:206 (No transformation, provided as part of mapping)
f. Second Action is Static NVGRE encap with GRE key '100'.
g. Underlay DIP shall be 50.2.2.6 (from mapping), Underlay SIP shall be 55.1.2.3 (from ENI)

3. Packet destined to 10.2.0.9 from 10.1.1.2:
a. LPM lookup hits for entry 10.2.0.0/24
b. The action in this case is "vnet"
c. Next lookup is in the mapping table and mapping table action here is "privatelink"
d. First Action for "privatelink" is 4to6 transposition
e. Packet gets transformed as:
For Overlay SIP, use Overlay SIP prefix -> Overlay SIP fd41:108:20:d204::200:a02:9;
Overlay DIP 2603:10e1:100:2::3402:206 (No transformation, provided as part of mapping)
f. Second Action is Static NVGRE encap with GRE key '100'.
g. Underlay DIP shall be 50.2.2.6 (from mapping), Underlay SIP shall be 55.1.2.3 (from ENI)
h. Mapping gives the tunnel info for final encap - nsg_tunnel_1
i. Packet shall be encapsulated with Outer DIP as 100.8.1.2 and SIP as VIP of this originating appliance card with VNI of 101.
j. Inbound flow shall be similar to PL and outer encap shall be of the SLB MUX and not of the NSG appliance.
1. Packet destined to 10.1.0.8 from 10.1.1.1:
1. LPM lookup hits for entry 10.1.0.8/32
2. The action in this case is "vnet"
3. Next lookup is in the mapping table and mapping table action here is "privatelink"
4. First Action for "privatelink" is 4to6 transposition
5. As per **3.6.3.2**, the final overlay SIP is `fd41:108:20:cb3a:16e5:ff71:a01:101`:
- Start with the original SIP `10.1.1.1` and convert it to IPv6 to give `::a01:101`.
- The mapping table `overlay_sip_prefix` has the mask `ffff:ffff:ffff:ffff:ffff:ffff::`, which means that bytes 1-12 of the final SIP are cleared. The IP remains `::a01:101`
- `overlay_sip_prefix.address` is written, giving `fd41:108:20:abc:abc::a01:101`.
- `pl_sip_encoding` has the mask `::ffff:ffff:ffff:0:0` so bytes 7-12 are cleared giving `fd41:108:20::a01:101`.
- `pl_sip_encoding.address` is written, giving the final SIP `fd41:108:20:cb3a:16e5:ff71:a01:101`.
6. Similarly, the final overlay DIP is `2603:10e1:100:2::3401:203`:
- The original packet DIP is converted to IPv6, giving `::a01:108`.
- The `overlay_dip_prefix` mask is `ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff` which clears all bits, giving `::`.
- `overlay_dip_prefix.address` is written, giving `2603:10e1:100:2::3401:203`
7. Second Action is Static NVGRE encap with GRE key '100'.
8. Underlay DIP shall be 50.1.2.3 (from mapping), Underlay SIP shall be 55.1.2.3 (from ENI)
9. Metering:
- LPM route has metering bits configured
- Aggregated OR - 0x66
- Aggregated AND - 0x77
- Metering class is derived from (Agreggated OR & Agreggated AND) -> 0x66 used for accounting the traffic

2. Packet destined to 10.2.0.6 from 10.1.1.2:
1. LPM lookup hits for entry 10.2.0.0/24
2. The action in this case is "vnet"
3. Next lookup is in the mapping table and mapping table action here is "privatelink"
4. First Action for "privatelink" is 4to6 transposition
5. As per **3.6.3.2**, the final overlay SIP is `cca4:ac57:2546:cb3a:16e5:ff71:a01:102`
- Convert original SIP to IPv6 to get `::a01:102`
- Clear bits 1-12 and write `overlay_sip_prefix.address` to get `cca4:ac57:2546::a01:102`
- Clear bits 7-12 and write `pl_sip_encoding.address` to get `cca4:ac57:2546:cb3a:16e5:ff71:a01:102`
6. The final overlay DIP is `3332:0f1c:2878:c130:d6a0:a997:a02:6`
- Convert original DIP to IPv6: `::a02:6`
- Clear bits 1-12 and write `overlay_dip_prefix.address` to get `3332:0f1c:2878:c130:d6a0:a997:a02:6`.
6. Second Action is Static NVGRE encap with GRE key '100'.
7. Underlay DIP shall be 50.2.2.6 (from mapping), Underlay SIP shall be 55.1.2.3 (from ENI)

3. Packet destined to 10.2.0.9 from 10.1.1.2:
1. LPM lookup hits for entry 10.2.0.0/24
2. The action in this case is "vnet"
3. Next lookup is in the mapping table and mapping table action here is "privatelink"
4. First Action for "privatelink" is 4to6 transposition
5. Final overlay SIP is `35ea:8ec2:e511:cb3a:16e5:ff71:a01:102`:
- Convert original SIP to IPv6: `::a01:102`
- Apply `overlay_sip_prefix`: `35ea:8ec2:e511::a01:102`
- Apply `pl_sip_encoding`: `35ea:8ec2:e511:cb3a:16e5:ff71:a01:102`
6. Final overlay DIP is `f409:6491:d18e:d3ff:ad7a:3b6e:0702:a92a`.
- As in the first example, mask length is 128 bits so the entire value of `overlay_dip_prefix.address` is written.
7. Second Action is Static NVGRE encap with GRE key '100'.
8. Underlay DIP shall be 50.2.2.6 (from mapping), Underlay SIP shall be 55.1.2.3 (from ENI)
9. Mapping gives the tunnel info for final encap - nsg_tunnel_1
10. Packet shall be encapsulated with Outer DIP as 100.8.1.2 and SIP as VIP of this originating appliance card with VNI of 101.
11. Inbound flow shall be similar to PL and outer encap shall be of the SLB MUX and not of the NSG appliance.

#### 3.6.3.2 PL IPv6 Address Transformation
Privatelink uses bytes 1-12 of the overlay source IPv6 address to encode extra information. The encoding information is provided in `DASH_ENI_TABLE:pl_sip_encoding` and `DASH_VNET_MAPPING_TABLE:overlay_sip_prefix`. `overlay_sip_prefix` and `pl_sip_encoding` contain both an IP address as well as a network mask. The mask for `overlay_sip_prefix` is used to clear specific bits in the final source IPv6 address, then the IP address is used to populate those same bits (the same applies to `pl_sip_encoding`). This operation can be represented as follows:

```
final_overlay_sip = (((orig_packet_sip & ~overlay_sip_prefix.mask)
| overlay_sip_prefix.addr)
& ~pl_sip_encoding.mask)
| pl_sip_encoding.addr
```
where `&`, `|`, and `~` represent bitwise `AND`, `OR`, and `NOT`.

The same principle applies to `overlay_dip_prefix` and the final overlay destination IPv6 address:
```
final_overlay_dip = (orig_packet_dip & ~overlay_dip_prefix.mask)
| overlay_dip_prefix.addr
```

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