Merge bitcoin/bitcoin#22589: net, doc: update I2P hardcoded seeds and docs for 22.0

d2dffd5be4 doc: add info to i2p.md about IBD time and multiple networks (Jon Atack)
2962640c49 contrib, p2p: update I2P hardcoded seeds (Jon Atack)

Pull request description:

  - Update the I2P seeds with the latest ones I can connect to (feedback welcome).

  - Update the I2P doc with frequently asked and reported info: IBD speed and running with other networks.

ACKs for top commit:
  tryphe:
    ACK d2dffd5be4
  duncandean:
    ACK d2dffd5
  willcl-ark:
    ACK d2dffd5be4
  laanwj:
    ACK d2dffd5be4
  vasild:
    ACK d2dffd5be4

Tree-SHA512: 1edda0eb77b4e224b44961849b36c5a13e1eb14bdc50f909ec44d7fe926c259cada62404906594a1cf68ffd96254647ac49f24248214b42403ecebae45135e63

contrib/seeds/nodes_main.txt

@@ -677,12 +677,20 @@ tddeij4qigtjr6jfnrmq6btnirmq5msgwcsdpcdjr7atftm7cxlqztid.onion:8333
 vi5bnbxkleeqi6hfccjochnn65lcxlfqs4uwgmhudph554zibiusqnad.onion:8333
 xqt25cobm5zqucac3634zfght72he6u3eagfyej5ellbhcdgos7t2had.onion:8333
 
-# manually added 2021-05 for minimal i2p bootstrap support
-72l3ucjkuscrbiiepoehuwqgknyzgo7zuix5ty4puwrkyhtmnsga.b32.i2p:0
+# manually added 2021-08 for minimal i2p bootstrap support
+4hllr6w55mbtemb3ebvlzl4zj6qke4si7zcob5qdyg63mjgq624a.b32.i2p:0
+6s33jtpvwzkiej3nff5qm72slgqljxhxn62hdt6m7nvynqsxqdda.b32.i2p:0
+a5qsnv3maw77mlmmzlcglu6twje6ttctd3fhpbfwcbpmewx6fczq.b32.i2p:0
+bitcornrd36coazsbzsz4pdebyzvaplmsalq4kpoljmn6cg6x5zq.b32.i2p:0
 c4gfnttsuwqomiygupdqqqyy5y5emnk5c73hrfvatri67prd7vyq.b32.i2p:0
+dhtq2p76tyhi442aidb3vd2bv7yxxjuddpb2jydnnrl2ons5bhha.b32.i2p:0
 gehtac45oaghz54ypyopim64mql7oad2bqclla74l6tfeolzmodq.b32.i2p:0
 h3r6bkn46qxftwja53pxiykntegfyfjqtnzbm6iv6r5mungmqgmq.b32.i2p:0
 hnbbyjpxx54623l555sta7pocy3se4sdgmuebi5k6reesz5rjp6q.b32.i2p:0
-pjs7or2ctvteeo5tu4bwyrtydeuhqhvdprtujn4daxr75jpebjxa.b32.i2p:0
+i3hcdakiz2tyvggkwefvdjoi7444kgvd2mbdfizjvv43q7zukezq.b32.i2p:0
+jz3s4eurm5vzjresf4mwo7oni4bk36daolwxh4iqtewakylgkxmq.b32.i2p:0
+kokkmpquqlkptu5hkmzqlttsmtwxicldr4so7wqsufk6bwf32nma.b32.i2p:0
+kvrde7mcgjhz3xzeltwy4gs2rxdfbnbs2wc67mh2pt43wjmjnmbq.b32.i2p:0
+shh2ewyegnuwnmdse5kl5toybdvzkvk2yj4zcowz6iwhhh3ykdfa.b32.i2p:0
 wwbw7nqr3ahkqv62cuqfwgtneekvvpnuc4i4f6yo7tpoqjswvcwa.b32.i2p:0
 zsxwyo6qcn3chqzwxnseusqgsnuw3maqnztkiypyfxtya4snkoka.b32.i2p:0

doc/i2p.md

@@ -47,13 +47,21 @@ information in the debug log about your I2P configuration and connections. Run
 `bitcoin-cli help logging` for more information.
 
 It is possible to restrict outgoing connections in the usual way with
-`onlynet=i2p`. I2P support was added to Bitcoin Core in version 22.0 (mid 2021)
+`onlynet=i2p`. I2P support was added to Bitcoin Core in version 22.0 (mid-2021)
 and there may be fewer I2P peers than Tor or IP ones. Therefore, using
 `onlynet=i2p` alone (without other `onlynet=`) may make a node more susceptible
 to [Sybil attacks](https://en.bitcoin.it/wiki/Weaknesses#Sybil_attack). Use
 `bitcoin-cli -addrinfo` to see the number of I2P addresses known to your node.
 
-## I2P related information in Bitcoin Core
+Another consideration with `onlynet=i2p` is that the initial blocks download
+phase when syncing up a new node can be very slow. This phase can be sped up by
+using other networks, for instance `onlynet=onion`, at the same time.
+
+In general, a node can be run with both onion and I2P hidden services (or
+any/all of IPv4/IPv6/onion/I2P), which can provide a potential fallback if one
+of the networks has issues.
+
+## I2P-related information in Bitcoin Core
 
 There are several ways to see your I2P address in Bitcoin Core:
 - in the debug log (grep for `AddLocal`, the I2P address ends in `.b32.i2p`)

src/chainparamsseeds.h

@@ -683,12 +683,20 @@ static const uint8_t chainparams_seed_main[] = {
     0x04,0x20,0x98,0xc6,0x44,0x27,0x90,0x41,0xa6,0x98,0xf9,0x25,0x6c,0x59,0x0f,0x06,0x6d,0x44,0x59,0x0e,0xb2,0x46,0xb0,0xa4,0x37,0x88,0x69,0x8f,0xc1,0x32,0xcd,0x9f,0x15,0xd7,0x20,0x8d,
     0x04,0x20,0xaa,0x3a,0x16,0x86,0xea,0x59,0x09,0x04,0x78,0xe5,0x10,0x92,0xe1,0x1d,0xad,0xf7,0x56,0x2b,0xac,0xb0,0x97,0x29,0x63,0x30,0xf4,0x1b,0xcf,0xde,0xf3,0x28,0x0a,0x29,0x20,0x8d,
     0x04,0x20,0xbc,0x27,0xae,0x89,0xc1,0x67,0x73,0x0a,0x08,0x02,0xdf,0xb7,0xcc,0x94,0xc7,0x9f,0xf4,0x72,0x7a,0x9b,0x20,0x0c,0x5c,0x11,0x3d,0x22,0xd6,0x13,0x88,0x66,0x74,0xbf,0x20,0x8d,
-    0x05,0x20,0xfe,0x97,0xba,0x09,0x2a,0xa4,0x85,0x10,0xa1,0x04,0x7b,0x88,0x7a,0x5a,0x06,0x53,0x71,0x93,0x3b,0xf9,0xa2,0x2f,0xd9,0xe3,0x8f,0xa5,0xa2,0xac,0x1e,0x6c,0x6c,0x8c,0x00,0x00,
+    0x05,0x20,0xe1,0xd6,0xb8,0xfa,0xdd,0xeb,0x03,0x32,0x30,0x3b,0x20,0x6a,0xbc,0xaf,0x99,0x4f,0xa0,0xa2,0x72,0x48,0xfe,0x44,0xe0,0xf6,0x03,0xc1,0xbd,0xb6,0x24,0xd0,0xf6,0xb8,0x00,0x00,
+    0x05,0x20,0xf4,0xb7,0xb4,0xcd,0xf5,0xb6,0x54,0x82,0x27,0x6d,0x29,0x7b,0x06,0x7f,0x52,0x59,0xa0,0xb4,0xdc,0xf7,0x6f,0xb4,0x71,0xcf,0xcc,0xfb,0x6b,0x86,0xc2,0x57,0x80,0xc6,0x00,0x00,
+    0x05,0x20,0x07,0x61,0x26,0xd7,0x6c,0x05,0xbf,0xf6,0x2d,0x8c,0xca,0xc4,0x65,0xd3,0xd3,0xb2,0x49,0xe9,0xcc,0x53,0x1e,0xca,0x77,0x84,0xb6,0x10,0x5e,0xc2,0x5a,0xfe,0x28,0xb3,0x00,0x00,
+    0x05,0x20,0x0a,0x26,0x27,0x45,0xb1,0x1e,0xfc,0x27,0x03,0x32,0x0e,0x65,0x9e,0x3c,0x64,0x0e,0x33,0x50,0x3d,0x6c,0x90,0x17,0x0e,0x29,0xee,0x5a,0x58,0xdf,0x08,0xde,0xbf,0x73,0x00,0x00,
     0x05,0x20,0x17,0x0c,0x56,0xce,0x72,0xa5,0xa0,0xe6,0x23,0x06,0xa3,0xc7,0x08,0x43,0x18,0xee,0x3a,0x46,0x35,0x5d,0x17,0xf6,0x78,0x96,0xa0,0x9c,0x51,0xef,0xbe,0x23,0xfd,0x71,0x00,0x00,
+    0x05,0x20,0x19,0xe7,0x0d,0x3f,0xfe,0x9e,0x0e,0x8e,0x73,0x40,0x40,0xc3,0xba,0x8f,0x41,0xaf,0xf1,0x7b,0xa6,0x83,0x1b,0xc3,0xa4,0xe0,0x6d,0x6c,0x57,0xa7,0x36,0x5d,0x09,0xce,0x00,0x00,
     0x05,0x20,0x31,0x0f,0x30,0x0b,0x9d,0x70,0x0c,0x7c,0xf7,0x98,0x7e,0x1c,0xf4,0x33,0xdc,0x64,0x17,0xf7,0x00,0x7a,0x0c,0x04,0xb5,0x83,0xfc,0x5f,0xa6,0x52,0x39,0x79,0x63,0x87,0x00,0x00,
     0x05,0x20,0x3e,0xe3,0xe0,0xa9,0xbc,0xf4,0x2e,0x59,0xd9,0x20,0xee,0xdf,0x74,0x61,0x4d,0x99,0x0c,0x5c,0x15,0x30,0x9b,0x72,0x16,0x79,0x15,0xf4,0x7a,0xca,0x34,0xcc,0x81,0x99,0x00,0x00,
     0x05,0x20,0x3b,0x42,0x1c,0x25,0xf7,0xbf,0x79,0xed,0x6d,0x7d,0xef,0x65,0x30,0x7d,0xee,0x16,0x37,0x22,0x72,0x43,0x33,0x28,0x40,0xa3,0xaa,0xf4,0x48,0x49,0x67,0xb1,0x4b,0xfd,0x00,0x00,
-    0x05,0x20,0x7a,0x65,0xf7,0x47,0x42,0x9d,0x66,0x42,0x3b,0xb3,0xa7,0x03,0x6c,0x46,0x78,0x19,0x28,0x78,0x1e,0xa3,0x7c,0x67,0x44,0xb7,0x83,0x05,0xe3,0xfe,0xa5,0xe4,0x0a,0x6e,0x00,0x00,
+    0x05,0x20,0x46,0xce,0x21,0x81,0x48,0xce,0xa7,0x8a,0x98,0xca,0xb1,0x0b,0x51,0xa5,0xc8,0xff,0x39,0xc5,0x1a,0xa3,0xd3,0x02,0x32,0xa3,0x29,0xad,0x79,0xb8,0x7f,0x34,0x51,0x33,0x00,0x00,
+    0x05,0x20,0x4e,0x77,0x2e,0x12,0x91,0x67,0x6b,0x94,0xc4,0x92,0x2f,0x19,0x67,0x7d,0xcd,0x47,0x02,0xad,0xf8,0x60,0x72,0xed,0x73,0xf1,0x10,0x99,0x2c,0x05,0x61,0x66,0x55,0xd9,0x00,0x00,
+    0x05,0x20,0x53,0x94,0xa6,0x3e,0x14,0x82,0xd4,0xf9,0xd3,0xa7,0x53,0x33,0x05,0xce,0x72,0x64,0xed,0x74,0x09,0x63,0x8f,0x24,0xef,0xda,0x12,0xa1,0x55,0xe0,0xd8,0xbb,0xd3,0x58,0x00,0x00,
+    0x05,0x20,0x55,0x62,0x32,0x7d,0x82,0x32,0x4f,0x9d,0xdf,0x24,0x5c,0xed,0x8e,0x1a,0x5a,0x8d,0xc6,0x50,0xb4,0x32,0xd5,0x85,0xef,0xb0,0xfa,0x7c,0xf9,0xbb,0x25,0x89,0x6b,0x03,0x00,0x00,
+    0x05,0x20,0x91,0xcf,0xa2,0x5b,0x04,0x33,0x69,0x66,0xb0,0x72,0x27,0x54,0xbe,0xcd,0xd8,0x08,0xeb,0x95,0x55,0x5a,0xc2,0x79,0x91,0x3a,0xd9,0xf2,0x2c,0x73,0x9f,0x78,0x50,0xca,0x00,0x00,
     0x05,0x20,0xb5,0x83,0x6f,0xb6,0x11,0xd8,0x0e,0xa8,0x57,0xda,0x15,0x20,0x5b,0x1a,0x6d,0x21,0x15,0x5a,0xbd,0xb4,0x17,0x11,0xc2,0xfb,0x0e,0xfc,0xde,0xe8,0x26,0x56,0xa8,0xac,0x00,0x00,
     0x05,0x20,0xcc,0xaf,0x6c,0x3b,0xd0,0x13,0x76,0x23,0xc3,0x36,0xbb,0x64,0x4a,0x4a,0x06,0x93,0x69,0x6d,0xb0,0x10,0x6e,0x66,0xa4,0x61,0xf8,0x2d,0xe7,0x80,0x72,0x4d,0x53,0x94,0x00,0x00,
 };