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// Copyright (C) 2019-2024 Algorand, Inc.
// This file is part of go-algorand
//
// go-algorand is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// go-algorand is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with go-algorand. If not, see <https://www.gnu.org/licenses/>.
package config
import (
"fmt"
"net/url"
"regexp"
"strings"
"github.com/algorand/go-algorand/protocol"
)
// DNSBootstrap represents parsed / validated components derived from a DNSBootstrapID
type DNSBootstrap struct {
PrimarySRVBootstrap string
// Optional Fields
BackupSRVBootstrap string
// Per documentation, thread-safe save for configuration method
DedupExp *regexp.Regexp
}
var networkBootstrapOverrideMap = map[protocol.NetworkID]DNSBootstrap{
Devnet: {
PrimarySRVBootstrap: "devnet.algodev.network",
BackupSRVBootstrap: "",
DedupExp: nil,
},
Betanet: {
PrimarySRVBootstrap: "betanet.algodev.network",
BackupSRVBootstrap: "",
DedupExp: nil,
},
Alphanet: {
PrimarySRVBootstrap: "alphanet.algodev.network",
BackupSRVBootstrap: "",
DedupExp: nil,
},
}
var nameExp = regexp.MustCompile(`<name>\.?`)
// Error strings
const (
bootstrapErrorEmpty = "DNSBootstrapID must be non-empty and a valid URL"
bootstrapErrorInvalidFormat = "invalid formatted DNSBootstrapID"
bootstrapErrorParsingQueryParams = "error parsing query params from DNSBootstrapID"
bootstrapErrorInvalidNameMacroUsage = "invalid usage of <name> macro in dedup param; must be at the beginning of the expression"
bootstrapDedupRegexDoesNotCompile = "dedup regex does not compile"
)
// For supported networks, supports template formats like
// `<network>.algorand.network?backup=<network>.algorand.net&dedup=<name>.algorand-<network>.(net|network)`
/**
* Validates and parses a DNSBootstrapID into a DNSBootstrap struct. We use Golang's url.ParseQuery as
* a convenience to parse out the ID and parameters (as the rules overlap cleanly).
*
* Non-exhaustive examples of valid formats:
*
* 1. <network>.algorand.network
* 2. myawesomebootstrap-<network>.specialdomain.com
* 3. <network>.algorand.network?backup=<network>.algorand.net
* 4. <network>.algorand.network?backup=<network>.algorand.net&dedup=<name>.algorand-<network>.(net|network)
* 5. <network>.algorand.network?backup=<network>.algorand.net&dedup=<name>.algorand-<network>.(net|network)
* 6. mybootstrap-<network>.sd.com?backup=mybackup-<network>.asd.net&dedup=<name>.md-<network>.(com|net)
*
* A few notes:
* 1. The network parameter to this function is substituted into the dnsBootstrapID anywhere that <network> appears.
* 2. The backup parameter's presence in the dNSBootstrapID is optional
*
* On the dedup mask/expression in particular:
* 1. The dedup mask/expression is intended to be used to deduplicate SRV records returned from the primary and backup DNS servers
* 2. It is optional, even if backup is present. The dedup mask/expression must be a valid regular expression if set.
* 3. If the <name> macro is used in the dedup mask/expression (in most circumstances, recommended), it must be at the beginning of the expression. It is intended as a placeholder for unique server names.
*
* @param dnsBootstrapID The DNSBootstrapID to parse
* @param network The network to substitute into the DNSBootstrapID
* @param defaultTemplateOverridden Whether the default template was overridden at runtime
* @return A DNSBootstrap struct if successful, error otherwise
*/
func parseDNSBootstrap(dnsBootstrapID string, network protocol.NetworkID, defaultTemplateOverridden bool) (*DNSBootstrap, error) {
// For several non-mainnet/testnet networks, we essentially ignore the bootstrap and use our own
// if template was not overridden
if !defaultTemplateOverridden {
bootstrap, exists := networkBootstrapOverrideMap[network]
if exists {
return &bootstrap, nil
}
}
// Normalize the dnsBootstrapID and insert the network
dnsBootstrapID = strings.Replace(strings.TrimSpace(strings.ToLower(dnsBootstrapID)), "<network>", string(network), -1)
if dnsBootstrapID == "" {
return nil, fmt.Errorf(bootstrapErrorEmpty)
}
parsedTemplate, err := url.Parse(dnsBootstrapID)
if err != nil || parsedTemplate.Host == "" {
// Try parsing with scheme prepended
var err2 error
parsedTemplate, err2 = url.Parse("https://" + dnsBootstrapID)
if err2 != nil {
return nil, fmt.Errorf("%s: %s, orig error: %s, with scheme error: %s",
bootstrapErrorInvalidFormat, dnsBootstrapID, err, err2)
}
}
m, err3 := url.ParseQuery(parsedTemplate.RawQuery)
if err3 != nil {
return nil, fmt.Errorf("%s: %s, error: %s", bootstrapErrorParsingQueryParams, dnsBootstrapID, err3)
}
backupBootstrapParam := m["backup"]
var backupSRVBootstrap string
if len(backupBootstrapParam) != 0 && backupBootstrapParam[0] != "" {
backupSRVBootstrap = backupBootstrapParam[0]
}
var dedupExp *regexp.Regexp
if backupSRVBootstrap != "" {
//dedup mask is optional, even with backup present
dedupParam := m["dedup"]
if len(dedupParam) != 0 && dedupParam[0] != "" {
// If <name> shows up anywhere other than the beginning of the dedup expression, we return an error.
nameMacroLocations := nameExp.FindAllStringIndex(dedupParam[0], -1)
for _, loc := range nameMacroLocations {
if loc[0] != 0 {
return nil, fmt.Errorf("%s: %s", bootstrapErrorInvalidNameMacroUsage, dnsBootstrapID)
}
}
// If the string happens to start with <name>, we replace it with an empty string.
dedupParam[0] = nameExp.ReplaceAllString(dedupParam[0], "")
var err4 error
dedupExp, err4 = regexp.Compile("(" + dedupParam[0] + ")")
if err4 != nil {
return nil, fmt.Errorf("%s: %s, error: %s", bootstrapDedupRegexDoesNotCompile, dnsBootstrapID, err4)
}
}
}
return &DNSBootstrap{PrimarySRVBootstrap: parsedTemplate.Host, BackupSRVBootstrap: backupSRVBootstrap, DedupExp: dedupExp}, nil
}
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