capture and return errors in ConntrackDeleteFilters

Signed-off-by: Daman Arora <aroradaman@gmail.com>

conntrack_linux.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"strings"
 	"time"
 
 	"github.com/vishvananda/netlink/nl"
@@ -158,21 +159,27 @@ func (h *Handle) ConntrackDeleteFilters(table ConntrackTableType, family InetFam
 	}
 
 	var matched uint
+	var errMsgs []string
 	for _, dataRaw := range res {
 		flow := parseRawData(dataRaw)
 		for _, filter := range filters {
 			if match := filter.MatchConntrackFlow(flow); match {
 				req2 := h.newConntrackRequest(table, family, nl.IPCTNL_MSG_CT_DELETE, unix.NLM_F_ACK)
 				// skip the first 4 byte that are the netfilter header, the newConntrackRequest is adding it already
 				req2.AddRawData(dataRaw[4:])
-				req2.Execute(unix.NETLINK_NETFILTER, 0)
-				matched++
-				// flow is already deleted, no need to match on other filters and continue to the next flow.
-				break
+				if _, err = req2.Execute(unix.NETLINK_NETFILTER, 0); err != nil {
+					errMsgs = append(errMsgs, fmt.Sprintf("failed to delete conntrack flow '%s': %s", flow.String(), err.Error()))
+				} else {
+					matched++
+					// flow is already deleted, no need to match on other filters and continue to the next flow.
+					break
+				}
 			}
 		}
 	}
-
+	if len(errMsgs) > 0 {
+		return matched, fmt.Errorf(strings.Join(errMsgs, "; "))
+	}
 	return matched, nil
 }