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@@ -26,9 +26,9 @@ import (
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"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/prng"
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)
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-// DownloadURL specifies a URL for downloading resources along with parameters
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-// for the download strategy.
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-type DownloadURL struct {
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+// TransferURL specifies a URL for uploading or downloading resources along
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+// with parameters for the transfer strategy.
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+type TransferURL struct {
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// URL is the location of the resource. This string is slightly obfuscated
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// with base64 encoding to mitigate trivial binary executable string scanning.
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@@ -39,81 +39,81 @@ type DownloadURL struct {
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// only be set to true when the resource has its own verification mechanism.
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SkipVerify bool
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- // OnlyAfterAttempts specifies how to schedule this URL when downloading
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+ // OnlyAfterAttempts specifies how to schedule this URL when transferring
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// the same resource (same entity, same ETag) from multiple different
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// candidate locations. For a value of N, this URL is only a candidate
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- // after N rounds of attempting the download from other URLs.
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+ // after N rounds of attempting the transfer to or from other URLs.
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OnlyAfterAttempts int
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}
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-// DownloadURLs is a list of download URLs.
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-type DownloadURLs []*DownloadURL
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+// TransferURLs is a list of transfer URLs.
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+type TransferURLs []*TransferURL
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// DecodeAndValidate validates a list of download URLs.
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//
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-// At least one DownloadURL in the list must have OnlyAfterAttempts of 0,
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-// or no DownloadURL would be selected on the first attempt.
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-func (d DownloadURLs) DecodeAndValidate() error {
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+// At least one TransferURL in the list must have OnlyAfterAttempts of 0,
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+// or no TransferURL would be selected on the first attempt.
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+func (t TransferURLs) DecodeAndValidate() error {
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hasOnlyAfterZero := false
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- for _, downloadURL := range d {
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- if downloadURL.OnlyAfterAttempts == 0 {
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+ for _, transferURL := range t {
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+ if transferURL.OnlyAfterAttempts == 0 {
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hasOnlyAfterZero = true
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}
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- decodedURL, err := base64.StdEncoding.DecodeString(downloadURL.URL)
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+ decodedURL, err := base64.StdEncoding.DecodeString(transferURL.URL)
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if err != nil {
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return errors.Tracef("failed to decode URL: %s", err)
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}
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- downloadURL.URL = string(decodedURL)
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+ transferURL.URL = string(decodedURL)
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}
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if !hasOnlyAfterZero {
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- return errors.Tracef("must be at least one DownloadURL with OnlyAfterAttempts = 0")
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+ return errors.Tracef("must be at least one TransferURL with OnlyAfterAttempts = 0")
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}
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return nil
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}
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-// Select chooses a DownloadURL from the list.
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+// Select chooses a TransferURL from the list.
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//
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// The first return value is the canonical URL, to be used
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-// as a key when storing information related to the DownloadURLs,
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+// as a key when storing information related to the TransferURLs,
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// such as an ETag.
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//
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-// The second return value is the chosen download URL, which is
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+// The second return value is the chosen transfer URL, which is
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// selected based at random from the candidates allowed in the
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// specified attempt.
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-func (d DownloadURLs) Select(attempt int) (string, string, bool) {
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+func (t TransferURLs) Select(attempt int) (string, string, bool) {
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// The first OnlyAfterAttempts = 0 URL is the canonical URL. This
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// is the value used as the key for SetUrlETag when multiple download
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// URLs can be used to fetch a single entity.
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canonicalURL := ""
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- for _, downloadURL := range d {
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- if downloadURL.OnlyAfterAttempts == 0 {
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- canonicalURL = downloadURL.URL
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+ for _, transferURL := range t {
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+ if transferURL.OnlyAfterAttempts == 0 {
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+ canonicalURL = transferURL.URL
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break
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}
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}
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candidates := make([]int, 0)
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- for index, URL := range d {
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+ for index, URL := range t {
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if attempt >= URL.OnlyAfterAttempts {
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candidates = append(candidates, index)
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}
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}
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if len(candidates) < 1 {
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- // This case is not expected, as decodeAndValidateDownloadURLs
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+ // This case is not expected, as decodeAndValidateTransferURLs
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// should reject configs that would have no candidates for
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// 0 attempts.
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return "", "", true
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}
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selection := prng.Intn(len(candidates))
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- downloadURL := d[candidates[selection]]
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+ transferURL := t[candidates[selection]]
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- return downloadURL.URL, canonicalURL, downloadURL.SkipVerify
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+ return transferURL.URL, canonicalURL, transferURL.SkipVerify
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}
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Rod Hynes