p2p/dnsdisc: add implementation of EIP-1459 (#20094)

This adds an implementation of node discovery via DNS TXT records to the
go-ethereum library. The implementation doesn't match EIP-1459 exactly,
the main difference being that this implementation uses separate merkle
trees for tree links and ENRs. The EIP will be updated to match p2p/dnsdisc.

To maintain DNS trees, cmd/devp2p provides a frontend for the p2p/dnsdisc
library. The new 'dns' subcommands can be used to create, sign and deploy DNS
discovery trees.

vendor/github.com/cloudflare/cloudflare-go/dns.go

@@ -0,0 +1,174 @@
+package cloudflare
+
+import (
+	"encoding/json"
+	"net/url"
+	"strconv"
+	"time"
+
+	"github.com/pkg/errors"
+)
+
+// DNSRecord represents a DNS record in a zone.
+type DNSRecord struct {
+	ID         string      `json:"id,omitempty"`
+	Type       string      `json:"type,omitempty"`
+	Name       string      `json:"name,omitempty"`
+	Content    string      `json:"content,omitempty"`
+	Proxiable  bool        `json:"proxiable,omitempty"`
+	Proxied    bool        `json:"proxied"`
+	TTL        int         `json:"ttl,omitempty"`
+	Locked     bool        `json:"locked,omitempty"`
+	ZoneID     string      `json:"zone_id,omitempty"`
+	ZoneName   string      `json:"zone_name,omitempty"`
+	CreatedOn  time.Time   `json:"created_on,omitempty"`
+	ModifiedOn time.Time   `json:"modified_on,omitempty"`
+	Data       interface{} `json:"data,omitempty"` // data returned by: SRV, LOC
+	Meta       interface{} `json:"meta,omitempty"`
+	Priority   int         `json:"priority"`
+}
+
+// DNSRecordResponse represents the response from the DNS endpoint.
+type DNSRecordResponse struct {
+	Result DNSRecord `json:"result"`
+	Response
+	ResultInfo `json:"result_info"`
+}
+
+// DNSListResponse represents the response from the list DNS records endpoint.
+type DNSListResponse struct {
+	Result []DNSRecord `json:"result"`
+	Response
+	ResultInfo `json:"result_info"`
+}
+
+// CreateDNSRecord creates a DNS record for the zone identifier.
+//
+// API reference: https://api.cloudflare.com/#dns-records-for-a-zone-create-dns-record
+func (api *API) CreateDNSRecord(zoneID string, rr DNSRecord) (*DNSRecordResponse, error) {
+	uri := "/zones/" + zoneID + "/dns_records"
+	res, err := api.makeRequest("POST", uri, rr)
+	if err != nil {
+		return nil, errors.Wrap(err, errMakeRequestError)
+	}
+
+	var recordResp *DNSRecordResponse
+	err = json.Unmarshal(res, &recordResp)
+	if err != nil {
+		return nil, errors.Wrap(err, errUnmarshalError)
+	}
+
+	return recordResp, nil
+}
+
+// DNSRecords returns a slice of DNS records for the given zone identifier.
+//
+// This takes a DNSRecord to allow filtering of the results returned.
+//
+// API reference: https://api.cloudflare.com/#dns-records-for-a-zone-list-dns-records
+func (api *API) DNSRecords(zoneID string, rr DNSRecord) ([]DNSRecord, error) {
+	// Construct a query string
+	v := url.Values{}
+	// Request as many records as possible per page - API max is 50
+	v.Set("per_page", "50")
+	if rr.Name != "" {
+		v.Set("name", rr.Name)
+	}
+	if rr.Type != "" {
+		v.Set("type", rr.Type)
+	}
+	if rr.Content != "" {
+		v.Set("content", rr.Content)
+	}
+
+	var query string
+	var records []DNSRecord
+	page := 1
+
+	// Loop over makeRequest until what we've fetched all records
+	for {
+		v.Set("page", strconv.Itoa(page))
+		query = "?" + v.Encode()
+		uri := "/zones/" + zoneID + "/dns_records" + query
+		res, err := api.makeRequest("GET", uri, nil)
+		if err != nil {
+			return []DNSRecord{}, errors.Wrap(err, errMakeRequestError)
+		}
+		var r DNSListResponse
+		err = json.Unmarshal(res, &r)
+		if err != nil {
+			return []DNSRecord{}, errors.Wrap(err, errUnmarshalError)
+		}
+		records = append(records, r.Result...)
+		if r.ResultInfo.Page >= r.ResultInfo.TotalPages {
+			break
+		}
+		// Loop around and fetch the next page
+		page++
+	}
+	return records, nil
+}
+
+// DNSRecord returns a single DNS record for the given zone & record
+// identifiers.
+//
+// API reference: https://api.cloudflare.com/#dns-records-for-a-zone-dns-record-details
+func (api *API) DNSRecord(zoneID, recordID string) (DNSRecord, error) {
+	uri := "/zones/" + zoneID + "/dns_records/" + recordID
+	res, err := api.makeRequest("GET", uri, nil)
+	if err != nil {
+		return DNSRecord{}, errors.Wrap(err, errMakeRequestError)
+	}
+	var r DNSRecordResponse
+	err = json.Unmarshal(res, &r)
+	if err != nil {
+		return DNSRecord{}, errors.Wrap(err, errUnmarshalError)
+	}
+	return r.Result, nil
+}
+
+// UpdateDNSRecord updates a single DNS record for the given zone & record
+// identifiers.
+//
+// API reference: https://api.cloudflare.com/#dns-records-for-a-zone-update-dns-record
+func (api *API) UpdateDNSRecord(zoneID, recordID string, rr DNSRecord) error {
+	rec, err := api.DNSRecord(zoneID, recordID)
+	if err != nil {
+		return err
+	}
+	// Populate the record name from the existing one if the update didn't
+	// specify it.
+	if rr.Name == "" {
+		rr.Name = rec.Name
+	}
+	rr.Type = rec.Type
+	uri := "/zones/" + zoneID + "/dns_records/" + recordID
+	res, err := api.makeRequest("PATCH", uri, rr)
+	if err != nil {
+		return errors.Wrap(err, errMakeRequestError)
+	}
+	var r DNSRecordResponse
+	err = json.Unmarshal(res, &r)
+	if err != nil {
+		return errors.Wrap(err, errUnmarshalError)
+	}
+	return nil
+}
+
+// DeleteDNSRecord deletes a single DNS record for the given zone & record
+// identifiers.
+//
+// API reference: https://api.cloudflare.com/#dns-records-for-a-zone-delete-dns-record
+func (api *API) DeleteDNSRecord(zoneID, recordID string) error {
+	uri := "/zones/" + zoneID + "/dns_records/" + recordID
+	res, err := api.makeRequest("DELETE", uri, nil)
+	if err != nil {
+		return errors.Wrap(err, errMakeRequestError)
+	}
+	var r DNSRecordResponse
+	err = json.Unmarshal(res, &r)
+	if err != nil {
+		return errors.Wrap(err, errUnmarshalError)
+	}
+	return nil
+}