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Begin adding session tables, debug infos

This commit is contained in:
Nico Schottelius 2019-05-02 13:54:31 +02:00
parent 879abe94c2
commit 02fc065c1d
4 changed files with 176 additions and 11 deletions
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134
doc/plan.org
View File

@ -228,13 +228,61 @@
| 2019-04-23 | | |
| | Meet Laurent | |
| | | |
| | General | |
| | - Get a better understanding of what others did | |
| | | |
| | Review docs / specs | |
| | - Jool EAMT/SIIT | |
| | - Jool EAMT/SIIT fully | |
| | | |
| | - IPv4 embedding | |
| | * Motivation/objective: working with real world DNS64 | |
| | * RFC6052 suffix support | |
| | * RFC4291 IPv4-Compatible IPv6 Address (16 0s) | |
| | * RFC4291 IPv4-Mapped IPv6 Address (16 1s) | |
| | | |
| | - Session handling | |
| | * RFC6145: Translation ip/icmp, obsoleted by RFC 7915 | |
| | * RFC6146: NAT64 definition, only TCP, UDP, and ICMP traffic | |
| | * RFC6052: embedding support | |
| | * Mode: IPv6 outgoing -> "masquarading" | |
| | * Mode: IPv4 | |
| | | |
| | - Translation details | |
| | * How to handle ICMP4->icmp6 correctly (RFC7915) | |
| | | |
| | - Hardware | |
| | * NetFPGA | |
| | * Hardware machine for software comparison? | |
| | | |
| | | |
| | New todos: | |
| | | |
| | - Translate fragment header | |
| | - Support MTU / packet too big | |
| | - Support PMTU, tcp mss | |
| | | |
| | | |
| | Meeting notes | |
| | - difference based | |
| | - first physical access | |
| | - tofino: if it compiles -> line rate | |
| | - chaining switches / OS -> single port rate | |
| | - netpfga | |
| | - reason about what in hardware and what in software -> reason tradeoff | !!! |
| | - table gets full | |
| | | |
| | | |
| | Follow up: | |
| | | |
| | - what's the MTU of an interface? have a table | |
| | - have port/mtu | |
| | - total packeth length -> from IP | |
| | - tables not in data plane | |
| | - Meeting Hendrik | |
| | - Meeting Kamila | |
| | | |
| | | |
| | - 768k | |
| | | |
| | | |
| | | |
@ -1386,7 +1434,6 @@ Please make sure that it is installed and available in your $PATH:
** Motivation
TBD
** Translation mechanisms
@ -1775,7 +1822,6 @@ restart controller - check whether tables are applied correctly (type conversion
start tcpdump - start test program - stop tcpdump - add
pcap to git repo - git add-commit-push - git pull - start wireshark -
debug packets - analyse code - goto 1
*** Setting up a system for working on P4 on devuan
**** Scripts in the wild
https://github.com/nsg-ethz/p4-learning/blob/master/vm/bin/update-p4c.sh
@ -1786,13 +1832,42 @@ debug packets - analyse code - goto 1
[21:24] line:~% sudo apt install libthrift-dev
[21:26] line:~% sudo apt install thrift-compiler
libnanomsg-dev libjudy-dev
*** TODO Session / dynamice mappings
**** General
- Have 1..n session IPv4 addresses
- Handle outgoing IPv6: create new session
- Handle in
***** TODO Case IPv6 initiator
- Mapping whole IPv4 Internet in /96 prefix
- Session information for mapping reply
- Timeout handling in controller
****** TODO IPv6 udp -> IPv4
- Got 4-5 tuple ([proto], src ip, src port, dst ip, dst port)
- Does not / never signal end
- Needs timeout for cleaning up
****** TODO IPv6 tcp -> IPv4
- Similar to udp
- react on FIN/RST (?) -- could be an addition
****** TODO IPv6 icmp6 -> IPv4
- usual protocol specific changes
- Session??
- src ip, dst ip, code ?
***** TODO Case IPv4 initiator
- Needs upper level protol
**** TODO tcp session
**** TODO udp session
**** TODO tcp session
** TODO Comparison with existing tools (Performance, Features)
*** Features
| What? | Description | State in P4 | References |
|-----------+------------------------------------------+-------------------+-----------------------------------------------|
| Jool EAMT | Mapping with tables, multiple entries | Supported | https://www.jool.mx/en/run-eam.html, RFC 7757 |
| Jool SIIT | Mapping IPv6 to range of IPv4, one entry | Supported by EAMT | |
| | | | |
| What? | Description | State in P4 | References |
|---------------------+------------------------------------------+-------------------+---------------------------------------------------------------------------------|
| Jool EAMT | Mapping with tables, multiple entries | Supported | https://www.jool.mx/en/eamt.html, https://www.jool.mx/en/run-eam.html, RFC 7757 |
| Jool SIIT | Mapping IPv6 to range of IPv4, one entry | Supported by EAMT | |
| Jool Stateful NAT64 | | | https://www.jool.mx/en/intro-xlat.html#stateful-nat64 |
| | | | https://www.jool.mx/en/run-nat64.html |
| | | | |
** P4 Possible Improvements / Current Challenges / Limitations
*** DONE cannot read key from table
**** log
@ -1990,6 +2065,23 @@ Linux package management, handling updates, etc.
Many constants double defined. Easy to make errors.
** Implementation description and limitations
*** Implementation description [move todos here]
**** TODO Support (non-) fragmentation
- if DF bit is not set in ipv4
**** TODO Supporting [different] MTUs
- sizes of headers are different
- packet might not fit into same mtu anymore
- send back "ICMP Packet Too Big messages to the sender." RFC7915
**** TODO pmtud support
- mss change
#+BEGIN_QUOTE
translator MUST send a
Packet Too Big error message or fragment the packet when the packet
size exceeds the MTU of the next-hop interface.
#+END_QUOTE
https://tools.ietf.org/html/rfc7915
*** Limitations
**** IPv4 embedding (RFC6052, RFC4291)
Supported is similar to the "IPv4-Compatible IPv6 Address" as defined by
@ -2006,7 +2098,14 @@ Also section 2.5.5.2 "IPv4-Mapped IPv6 Address"
Mac addresses: bit 0 = unicast (0)/multicast(1),
bit 1 = local (1)/global (0) - site wiki/mac
U/L bit is universal/local, bit 2; inverting: local = 0, global = 1
**** No fragmentation support (yet)
In line with RFC7915
#+BEGIN_QUOTE
Fragmented ICMP/ICMPv6 packets will not be translated by IP/ICMP translators.
#+END_QUOTE
**** No session handling (yet)
1:1 mappings. No (automatic) session.
**** IPv4 / IPv6 embedding
@ -2027,6 +2126,13 @@ bit 1 = local (1)/global (0) - site wiki/mac
handle packet.
Only has to be set, when packets originate from the switch/controller.
**** TODO No support of IPv4 options
- header is assumed to be always 20 octets
**** TODO Security issue: not checking checksums before
- Could be implemented
** References / Follow up
*** RFC 791 IPv4 https://tools.ietf.org/html/rfc791
*** RFC 792 ICMP https://tools.ietf.org/html/rfc792
@ -2051,8 +2157,20 @@ bit 1 = local (1)/global (0) - site wiki/mac
*** RFC 4443 ICMPv6 https://tools.ietf.org/html/rfc4443
*** RFC 4861: https://tools.ietf.org/html/rfc4861 Neighbor discovery
*** RFC 6052: https://tools.ietf.org/html/rfc6052 IPv6 Addressing of IPv4/IPv6 Translators - first NAT64??
*** RFC 6145 IP/ICMP Translation Algorithm
- Obsoleted by 7915
*** RFC 6146 Stateful nat http://tools.ietf.org/html/rfc6146
- Referenced from Jool
*** RFC 6147 DNS64 https://tools.ietf.org/html/rfc6147
*** RFC 6586 for deployment experiences using Stateful NAT64.
*** RFC 7757 Explicit Address Mappings for Stateless IP/ICMP Translation - https://tools.ietf.org/html/rfc7757
*** RFC 7915 IP/ICMP Translation Algorithm https://tools.ietf.org/html/rfc7915
- Requires RFC 6144
- MUST support one or more address mapping algorithms, which
are defined in Section 6.
- does not translate IPv6 extension headers except the Fragment Header.
*** EAMT/Jool: https://www.jool.mx/en/eamt.html
*** Solicited node multicast address https://en.wikipedia.org/wiki/Solicited-node_multicast_address
*** Scapy / IPv6: https://www.idsv6.de/Downloads/IPv6PacketCreationWithScapy.pdf

11
p4app/controller.py
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@ -38,7 +38,11 @@ table_id_fields = {
5: 'TABLE_V4_NETWORKS',
6: 'TABLE_ARP',
7: 'TABLE_ARP_EGRESS',
8: 'TABLE_ICMP'
8: 'TABLE_ICMP',
9: 'TABLE_NAT64_TCP',
10: 'TABLE_NAT64_UDP',
11: 'TABLE_NAT64_ICMP6',
12: 'TABLE_NAT64_SESSION'
}
table_proto = {
@ -85,7 +89,7 @@ class L2Controller(object):
self.info['v6_mask'] = 64
self.info['v6_nat64_mask'] = 96
self.info['v6_base'] = ipaddress.ip_network("2001:db8::/32")
self.info['v6_base'] = ipaddress.ip_network("2001:db8::/40")
self.info['v6_base_hostnet'] = ipaddress.ip_network("2001:db8::/48")
self.info['v6_gen'] = self.info['v6_base_hostnet'].subnets(new_prefix=self.info['v6_mask'])
@ -106,6 +110,9 @@ class L2Controller(object):
self.info['switch_suffix'] = 0x42
self.info['nat64_prefix'] = ipaddress.ip_network("64:ff9b::/96")
# /96 after the /40 pool we use above
self.info['nat64_prefix_dynamic'] = ipaddress.ip_network("2001:db8:100::/96")
self.v6_routes = {}
self.v6_routes[None] = []
self.v6_routes['base'] = []

4
p4src/headers.p4
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@ -25,6 +25,10 @@ const bit<16> TABLE_V4_NETWORKS = 5;
const bit<16> TABLE_ARP = 6;
const bit<16> TABLE_ARP_EGRESS = 7;
const bit<16> TABLE_ICMP = 8;
const bit<16> TABLE_NAT64_TCP = 9;
const bit<16> TABLE_NAT64_UDP = 10;
const bit<16> TABLE_NAT64_ICMP6 = 11;
const bit<16> TABLE_NAT64_SESSION = 12;
const bit<16> TYPE_IPV4 = 0x0800;

38
p4src/static-mapping.p4
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@ -232,6 +232,42 @@ Echo or Echo Reply Message
default_action = controller_debug_table_id(TABLE_NAT46);
}
/********************** NAT64 sessions ***********************************/
action nat64_create_session()
{
}
/* Used for detecting traffic that should have a session */
table nat64_session {
key = {
hdr.ipv6.dst_addr: lpm;
}
actions = {
controller_debug_table_id;
NoAction;
}
size = NAT64_TABLE_SIZE;
default_action = controller_debug_table_id(TABLE_NAT64_SESSION);
}
table nat64_tcp {
key = {
hdr.ipv6.src_addr: exact;
hdr.ipv6.dst_addr: exact;
hdr.tcp.src_port: exact;
hdr.tcp.dst_port: exact;
}
actions = {
controller_debug_table_id;
NoAction;
}
size = NAT64_TABLE_SIZE;
default_action = controller_debug_table_id(TABLE_NAT64_TCP);
}
/********************** ICMP6 + NDP + ICMP ***********************************/
@ -433,7 +469,7 @@ Echo or Echo Reply Message
/********************** APPLYING TABLES ***********************************/
apply {
if(hdr.ipv6.isValid()) {
if(nat64.apply().hit) { /* generic nat64 done */
if(nat64.apply().hit) { /* generic / static nat64 done */
if(hdr.icmp6.isValid()) {
nat64_icmp6_generic();