diff --git a/src/core/dhcp/nm-dhcp-utils.c b/src/core/dhcp/nm-dhcp-utils.c
index 949d87207f..8a9bd58cc6 100644
--- a/src/core/dhcp/nm-dhcp-utils.c
+++ b/src/core/dhcp/nm-dhcp-utils.c
@@ -32,11 +32,11 @@ ip4_process_dhcpcd_rfc3442_routes(const char     *iface,
                                   in_addr_t       address,
                                   guint32        *out_gwaddr)
 {
-    gs_free const char **routes = NULL;
-    const char         **r;
-    gboolean             have_routes = FALSE;
+    gs_free char **routes = NULL;
+    char         **r;
+    gboolean       have_routes = FALSE;
 
-    routes = nm_strsplit_set(str, " ");
+    routes = (char **) nm_strsplit_set(str, " ");
     if (!routes)
         return FALSE;
 
diff --git a/src/core/dns/nm-dns-manager.c b/src/core/dns/nm-dns-manager.c
index c746e71497..ec33c46427 100644
--- a/src/core/dns/nm-dns-manager.c
+++ b/src/core/dns/nm-dns-manager.c
@@ -1510,8 +1510,8 @@ _domain_track_is_shadowed(GHashTable  *ht,
                           const char **out_parent,
                           int         *out_parent_priority)
 {
-    char *parent;
-    int   parent_priority;
+    const char *parent;
+    int         parent_priority;
 
     if (!ht)
         return FALSE;
diff --git a/src/core/nm-checkpoint.c b/src/core/nm-checkpoint.c
index ffcf6e3aad..45ea3a73b6 100644
--- a/src/core/nm-checkpoint.c
+++ b/src/core/nm-checkpoint.c
@@ -160,7 +160,7 @@ parse_connection_from_shadowed_file(const char *path, GError **error)
 {
     nm_auto_unref_keyfile GKeyFile *keyfile  = NULL;
     gs_free char                   *base_dir = NULL;
-    char                           *sep;
+    const char                     *sep;
 
     keyfile = g_key_file_new();
     if (!g_key_file_load_from_file(keyfile, path, G_KEY_FILE_NONE, error))
diff --git a/src/core/platform/tests/test-link.c b/src/core/platform/tests/test-link.c
index fab6bd2efe..77e7e64121 100644
--- a/src/core/platform/tests/test-link.c
+++ b/src/core/platform/tests/test-link.c
@@ -123,7 +123,8 @@ software_add(NMLinkType link_type, const char *name)
         gboolean bond0_exists = !!nm_platform_link_get_by_ifname(NM_PLATFORM_GET, "bond0");
         int      r;
         const NMPlatformLnkBond nm_platform_lnk_bond_default = {
-            .mode = nmtst_rand_select(3, 1),
+            .mode        = nmtst_rand_select(3, 1),
+            .use_carrier = 1,
         };
 
         r = nm_platform_link_bond_add(NM_PLATFORM_GET, name, &nm_platform_lnk_bond_default, NULL);
diff --git a/src/core/settings/plugins/ifcfg-rh/nms-ifcfg-rh-reader.c b/src/core/settings/plugins/ifcfg-rh/nms-ifcfg-rh-reader.c
index b9e3f91920..728dccac99 100644
--- a/src/core/settings/plugins/ifcfg-rh/nms-ifcfg-rh-reader.c
+++ b/src/core/settings/plugins/ifcfg-rh/nms-ifcfg-rh-reader.c
@@ -77,7 +77,7 @@ get_full_file_path(const char *ifcfg_path, const char *file_path)
 {
     const char   *base    = file_path;
     gs_free char *dirname = NULL;
-    char         *p;
+    const char   *p;
 
     g_return_val_if_fail(ifcfg_path != NULL, NULL);
     g_return_val_if_fail(file_path != NULL, NULL);
diff --git a/src/core/supplicant/nm-supplicant-settings-verify.c b/src/core/supplicant/nm-supplicant-settings-verify.c
index 6e5e44d2f8..cca53d820f 100644
--- a/src/core/supplicant/nm-supplicant-settings-verify.c
+++ b/src/core/supplicant/nm-supplicant-settings-verify.c
@@ -212,18 +212,19 @@ validate_type_utf8(const struct Opt *opt, const char *value, const guint32 len)
 }
 
 static gboolean
-validate_type_keyword(const struct Opt *opt, const char *value, const guint32 len)
+validate_type_keyword(const struct Opt *opt, const char *value_in, const guint32 len)
 {
     gs_free char *value_free = NULL;
+    char         *value;
 
     nm_assert(opt);
-    nm_assert(value);
+    nm_assert(value_in);
 
     /* Allow everything */
     if (!opt->str_allowed)
         return TRUE;
 
-    value = nm_strndup_a(300, value, len, &value_free);
+    value = nm_strndup_a(300, value_in, len, &value_free);
 
     /* validate each space-separated word in 'value' */
 
diff --git a/src/libnm-core-aux-intern/nm-libnm-core-utils.c b/src/libnm-core-aux-intern/nm-libnm-core-utils.c
index 2d709e20ef..a39f645468 100644
--- a/src/libnm-core-aux-intern/nm-libnm-core-utils.c
+++ b/src/libnm-core-aux-intern/nm-libnm-core-utils.c
@@ -483,8 +483,8 @@ nm_utils_validate_shared_dhcp_range(const char *shared_dhcp_range,
                                     GPtrArray  *addresses,
                                     GError    **error)
 {
-    char         *start_address_str;
-    char         *end_address_str;
+    const char   *start_address_str;
+    const char   *end_address_str;
     NMIPAddress  *interface_address_with_prefix;
     NMIPAddr      interface_address;
     NMIPAddr      start_address;
@@ -825,7 +825,7 @@ nm_dns_uri_parse(int addr_family, const char *str, NMDnsServer *dns, GError **er
         addr = nm_strndup_a(100, addr_port, end - addr_port, &addr_heap);
 
         /* IPv6 link-local scope-id */
-        perc = strchr(addr, '%');
+        perc = (char *) strchr(addr, '%');
         if (perc) {
             *perc = '\0';
             if (g_strlcpy(dns->interface, perc + 1, sizeof(dns->interface))
diff --git a/src/libnm-core-impl/nm-setting-bridge.c b/src/libnm-core-impl/nm-setting-bridge.c
index c161843498..2145741204 100644
--- a/src/libnm-core-impl/nm-setting-bridge.c
+++ b/src/libnm-core-impl/nm-setting-bridge.c
@@ -472,17 +472,17 @@ nm_bridge_vlan_to_str(const NMBridgeVlan *vlan, GError **error)
 NMBridgeVlan *
 nm_bridge_vlan_from_str(const char *str, GError **error)
 {
-    NMBridgeVlan        *vlan   = NULL;
-    gs_free const char **tokens = NULL;
-    guint                i, vid_start, vid_end = 0;
-    gboolean             pvid     = FALSE;
-    gboolean             untagged = FALSE;
-    char                *c;
+    NMBridgeVlan  *vlan   = NULL;
+    gs_free char **tokens = NULL;
+    guint          i, vid_start, vid_end = 0;
+    gboolean       pvid     = FALSE;
+    gboolean       untagged = FALSE;
+    char          *c;
 
     g_return_val_if_fail(str, NULL);
     g_return_val_if_fail(!error || !*error, NULL);
 
-    tokens = nm_utils_escaped_tokens_split(str, NM_ASCII_SPACES);
+    tokens = (char **) nm_utils_escaped_tokens_split(str, NM_ASCII_SPACES);
     if (!tokens || !tokens[0]) {
         g_set_error_literal(error,
                             NM_CONNECTION_ERROR,
diff --git a/src/libnm-core-impl/nm-setting.c b/src/libnm-core-impl/nm-setting.c
index 98424c76fc..3b3aecf1a6 100644
--- a/src/libnm-core-impl/nm-setting.c
+++ b/src/libnm-core-impl/nm-setting.c
@@ -4495,7 +4495,7 @@ nm_range_from_str(const char *str, GError **error)
     gs_free char *str_free = NULL;
     guint64       start;
     guint64       end = 0;
-    char         *c;
+    const char   *c;
 
     g_return_val_if_fail(str, NULL);
     g_return_val_if_fail(!error || !*error, NULL);
diff --git a/src/libnm-systemd-shared/src/basic/sort-util.h b/src/libnm-systemd-shared/src/basic/sort-util.h
index 9c818bd747..a3bfb32c1d 100644
--- a/src/libnm-systemd-shared/src/basic/sort-util.h
+++ b/src/libnm-systemd-shared/src/basic/sort-util.h
@@ -25,15 +25,18 @@ void *xbsearch_r(const void *key, const void *base, size_t nmemb, size_t size,
  * Normal bsearch requires base to be nonnull. Here were require
  * that only if nmemb > 0.
  */
-static inline void* bsearch_safe(const void *key, const void *base,
+static inline void* bsearch_safe_internal(const void *key, const void *base,
                                  size_t nmemb, size_t size, comparison_fn_t compar) {
         if (nmemb <= 0)
                 return NULL;
 
         assert(base);
-        return bsearch(key, base, nmemb, size, compar);
+        return (void*) bsearch(key, base, nmemb, size, compar);
 }
 
+#define bsearch_safe(key, base, nmemb, size, compar) \
+        const_generic((base), bsearch_safe_internal(key, base, nmemb, size, compar))
+
 #define typesafe_bsearch(k, b, n, func)                                 \
         ({                                                              \
                 const typeof((b)[0]) *_k = k;                           \
diff --git a/src/libnm-systemd-shared/src/basic/string-util.c b/src/libnm-systemd-shared/src/basic/string-util.c
index 5efd11eabc..52160fe3e2 100644
--- a/src/libnm-systemd-shared/src/basic/string-util.c
+++ b/src/libnm-systemd-shared/src/basic/string-util.c
@@ -1470,7 +1470,7 @@ ssize_t strlevenshtein(const char *x, const char *y) {
         return t1[yl];
 }
 
-char* strrstr(const char *haystack, const char *needle) {
+char* strrstr_internal(const char *haystack, const char *needle) {
         /* Like strstr() but returns the last rather than the first occurrence of "needle" in "haystack". */
 
         if (!haystack || !needle)
@@ -1479,7 +1479,7 @@ char* strrstr(const char *haystack, const char *needle) {
         /* Special case: for the empty string we return the very last possible occurrence, i.e. *after* the
          * last char, not before. */
         if (*needle == 0)
-                return strchr(haystack, 0);
+                return (char*) strchr(haystack, 0);
 
         for (const char *p = strstr(haystack, needle), *q; p; p = q) {
                 q = strstr(p + 1, needle);
diff --git a/src/libnm-systemd-shared/src/basic/string-util.h b/src/libnm-systemd-shared/src/basic/string-util.h
index 91e63c9b12..5d2b5dfb16 100644
--- a/src/libnm-systemd-shared/src/basic/string-util.h
+++ b/src/libnm-systemd-shared/src/basic/string-util.h
@@ -27,24 +27,28 @@
 #define URI_UNRESERVED      ALPHANUMERICAL "-._~"       /* [RFC3986] */
 #define URI_VALID           URI_RESERVED URI_UNRESERVED /* [RFC3986] */
 
-static inline char* strstr_ptr(const char *haystack, const char *needle) {
+static inline char* strstr_ptr_internal(const char *haystack, const char *needle) {
         if (!haystack || !needle)
                 return NULL;
-        return strstr(haystack, needle);
+        return (char*) strstr(haystack, needle);
 }
 
-static inline char* strstrafter(const char *haystack, const char *needle) {
-        char *p;
+#define strstr_ptr(haystack, needle) \
+        const_generic(haystack, strstr_ptr_internal(haystack, needle))
 
+static inline char* strstrafter_internal(const char *haystack, const char *needle) {
         /* Returns NULL if not found, or pointer to first character after needle if found */
 
-        p = strstr_ptr(haystack, needle);
+        char *p = (char*) strstr_ptr(haystack, needle);
         if (!p)
                 return NULL;
 
         return p + strlen(needle);
 }
 
+#define strstrafter(haystack, needle) \
+        const_generic(haystack, strstrafter_internal(haystack, needle))
+
 static inline const char* strnull(const char *s) {
         return s ?: "(null)";
 }
@@ -300,6 +304,8 @@ bool version_is_valid_versionspec(const char *s);
 
 ssize_t strlevenshtein(const char *x, const char *y);
 
-char* strrstr(const char *haystack, const char *needle);
+char* strrstr_internal(const char *haystack, const char *needle);
+#define strrstr(haystack, needle) \
+        const_generic(haystack, strrstr_internal(haystack, needle))
 
 size_t str_common_prefix(const char *a, const char *b);
diff --git a/src/libnm-systemd-shared/src/fundamental/macro-fundamental.h b/src/libnm-systemd-shared/src/fundamental/macro-fundamental.h
index abdfb9b6bd..a89994e273 100644
--- a/src/libnm-systemd-shared/src/fundamental/macro-fundamental.h
+++ b/src/libnm-systemd-shared/src/fundamental/macro-fundamental.h
@@ -511,4 +511,11 @@ assert_cc(STRLEN(__FILE__) > STRLEN(RELATIVE_SOURCE_PATH) + 1);
 #define PROJECT_FILE (&__FILE__[STRLEN(RELATIVE_SOURCE_PATH) + 1])
 #else /* NM_IGNORED */
 #define PROJECT_FILE __FILE__
-#endif /* NM_IGNORED */
\ No newline at end of file
+#endif /* NM_IGNORED */
+
+/* This macro is used to have a const-returning and non-const returning version of a function based on
+ * whether its first argument is const or not (e.g. strstr()). */
+#define const_generic(ptr, call)                              \
+        _Generic(0 ? (ptr) : (void*) 1,                       \
+                 const void*: (const typeof(*call)*) (call),  \
+                 void*: (call))
diff --git a/src/libnm-udev-aux/nm-udev-utils.c b/src/libnm-udev-aux/nm-udev-utils.c
index 744d03ce9e..9e43dd26b9 100644
--- a/src/libnm-udev-aux/nm-udev-utils.c
+++ b/src/libnm-udev-aux/nm-udev-utils.c
@@ -92,7 +92,8 @@ _subsystem_split(const char  *subsystem_full,
                  const char **out_devtype,
                  char       **to_free)
 {
-    char *tmp, *s;
+    char       *tmp;
+    const char *s;
 
     nm_assert(subsystem_full);
     nm_assert(out_subsystem);
@@ -101,12 +102,12 @@ _subsystem_split(const char  *subsystem_full,
 
     s = strstr(subsystem_full, "/");
     if (s) {
-        tmp            = g_strdup(subsystem_full);
-        s              = &tmp[s - subsystem_full];
-        *s             = '\0';
-        *out_subsystem = tmp;
-        *out_devtype   = &s[1];
-        *to_free       = tmp;
+        tmp                     = g_strdup(subsystem_full);
+        tmp[s - subsystem_full] = '\0';
+        s                       = &tmp[s - subsystem_full];
+        *out_subsystem          = tmp;
+        *out_devtype            = &s[1];
+        *to_free                = tmp;
     } else {
         *out_subsystem = subsystem_full;
         *out_devtype   = NULL;
diff --git a/src/nm-initrd-generator/nmi-cmdline-reader.c b/src/nm-initrd-generator/nmi-cmdline-reader.c
index 5cdb3bcdb3..f9b0fa161b 100644
--- a/src/nm-initrd-generator/nmi-cmdline-reader.c
+++ b/src/nm-initrd-generator/nmi-cmdline-reader.c
@@ -1177,7 +1177,7 @@ reader_parse_rd_znet(Reader *reader, char *argument, gboolean net_ifnames)
 {
     const char     *nettype;
     const char     *subchannels[4] = {0, 0, 0, 0};
-    const char     *tmp;
+    char           *tmp;
     gs_free char   *ifname          = NULL;
     gs_free char   *str_subchannels = NULL;
     const char     *prefix;
@@ -1248,8 +1248,8 @@ reader_parse_rd_znet(Reader *reader, char *argument, gboolean net_ifnames)
                  NULL);
 
     while ((tmp = get_word(&argument, ',')) != NULL) {
-        const char *key;
-        char       *val;
+        char *key;
+        char *val;
 
         val = strchr(tmp, '=');
         if (!val) {