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prefix_fetcher.go
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/
prefix_fetcher.go
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// Copyright 2020 Anapaya Systems
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package grpc
import (
"context"
"net"
"github.com/scionproto/scion/gateway/control"
"github.com/scionproto/scion/pkg/addr"
"github.com/scionproto/scion/pkg/grpc"
"github.com/scionproto/scion/pkg/private/serrors"
gpb "github.com/scionproto/scion/pkg/proto/gateway"
"github.com/scionproto/scion/pkg/snet"
)
// PrefixFetcher fetches prefixes from a gateway in a specific remote.
type PrefixFetcher struct {
Remote addr.IA
Pather control.PathMonitorRegistration
Dialer grpc.Dialer
}
func (f PrefixFetcher) Prefixes(ctx context.Context, gateway *net.UDPAddr) ([]*net.IPNet, error) {
paths := f.Pather.Get().Paths
if len(paths) == 0 {
return nil, serrors.New("no path available")
}
conn, err := f.Dialer.Dial(ctx, &snet.UDPAddr{
IA: f.Remote,
Path: paths[0].Dataplane(),
NextHop: paths[0].UnderlayNextHop(),
Host: gateway,
})
if err != nil {
return nil, err
}
defer conn.Close()
client := gpb.NewIPPrefixesServiceClient(conn)
rep, err := client.Prefixes(ctx, &gpb.PrefixesRequest{}, grpc.RetryProfile...)
if err != nil {
return nil, serrors.WrapStr("receiving IP prefixes", err)
}
prefixes := make([]*net.IPNet, 0, len(rep.Prefixes))
for _, pb := range rep.Prefixes {
mask := net.CIDRMask(int(pb.Mask), len(pb.Prefix)*8)
if mask == nil {
continue
}
prefixes = append(prefixes, &net.IPNet{
IP: pb.Prefix,
Mask: mask,
})
}
return prefixes, nil
}